Commonwealth v. DiCicco , 470 Mass. 720 ( 2015 )


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    SJC-11672
    COMMONWEALTH   vs.   ROBERT DiCICCO.
    Middlesex.     November 4, 2014. - February 26, 2015.
    Present: Gants, C.J., Spina, Cordy, Botsford, Duffly, & Hines,
    JJ.
    Deoxyribonucleic Acid. Practice, Criminal, New trial,
    Postconviction relief. Evidence, Expert opinion,
    Scientific test. Witness, Expert.
    Indictment found and returned in the Superior Court
    Department on September 27, 1983.
    A motion for postconviction relief, filed on November 28,
    2007, was heard by Diane M. Kottmyer, J., and a motion for
    additional funds for the services of an expert witness was
    considered by her.
    After review by the Appeals Court, the Supreme Judicial
    Court granted leave to obtain further appellate review.
    David J. Nathanson (Michael A. Nam-Krane with him) for the
    defendant.
    Hallie White Speight, Assistant District Attorney, for the
    Commonwealth.
    Sara A. Colb, for New England Innocence Project, amicus
    curiae, submitted a brief.
    Ira L. Gant & Lisa M. Kavanaugh, Committee for Public
    Counsel Services, & Elizabeth A. Lunt, for Committee for Public
    Counsel Services Innocence Program & another, amici curiae,
    submitted a brief.
    2
    CORDY, J.   In 1984, the defendant was convicted by a jury
    of aggravated rape.   In July, 2005, the Superior Court clerk's
    office in Middlesex County located the trial exhibits, including
    the victim's blue jeans and underpants.     They had been stored in
    plastic bags since the trial.    Beginning in January, 2006, the
    defendant filed a series of motions to test the evidence for
    deoxyribonucleic acid (DNA).     These motions were granted and the
    State police crime laboratory (crime laboratory) and Orchid
    Cellmark (Cellmark), an independent laboratory, performed DNA
    testing on the victim's clothing.    The defendant subsequently
    moved for a new trial pursuant to Mass. R. Crim. P. 30 (b), as
    appearing in 
    435 Mass. 1501
    (1995), relying on the affidavit of
    Eric Carita (Carita), a forensic analyst employed by the
    Connecticut State laboratory,1 who opined that the defendant was
    excluded as the source of the male DNA on the victim's jeans
    based on "potential alleles."2    In July, 2010, a judge in the
    Superior Court (motion judge) held a two-day evidentiary hearing
    1
    Eric Carita is employed as a forensic science examiner in
    the nuclear deoxyribonucleic acid (DNA) casework unit at the
    Connecticut State laboratory. He has worked at that laboratory
    since 2003. Carita was the second DNA analyst that the
    defendant retained to examine the results of the DNA testing.
    2
    "A DNA profile for an individual is that combination of
    alleles, or versions of genes, possessed by the individual at
    the loci tested." Commonwealth v. Gaynor, 
    443 Mass. 245
    , 248
    n.1 (2005).
    3
    on the defendant's motion for postconviction relief, at which
    Carita and Christine Lemire, the crime laboratory analyst who
    performed the DNA analysis,3 testified.
    Subsequently, on March 28, 2011, the judge denied the
    defendant's motion for a new trial in a detailed memorandum of
    decision and order.    In an unpublished memorandum and order
    pursuant to its rule 1:28, the Appeals Court affirmed the
    denial.    See Commonwealth v. DiCicco, 
    84 Mass. App. Ct. 1128
    (2014).    We granted the defendant's application for further
    appellate review and conclude that the motion judge did not
    abuse her discretion in determining that, under Commonwealth v.
    Lanigan, 
    419 Mass. 15
    , 25-26 (1994), Carita's opinion was not
    sufficiently reliable to be placed before a jury, and the
    defendant's motion for a new trial was properly denied.
    Background.    We consider the facts as set forth in the
    motion judge's findings after an evidentiary hearing, which are
    supported by the evidence in the record.4    See Commonwealth v.
    Stephens, 
    451 Mass. 370
    , 372 (2008).
    1.    Evidence at the 1984 trial.   In August, 1983, the
    victim was walking home through a parking lot in Waltham
    3
    Christine Lemire is employed as a DNA analyst with the
    Massachusetts Forensic Technology Center (also commonly known as
    the State police crime laboratory [crime laboratory]). She has
    worked at that laboratory since 1996.
    4
    See note 22, infra.
    4
    sometime after 1:30 A.M. when she was attacked by two men.       One
    of these men, later identified as Vincent Park,5 grabbed the
    victim and forced her to the ground.     While Park pinned the
    victim down, the second man, subsequently identified as the
    defendant, pulled the victim's jeans and underwear down to her
    ankles.   As she struggled, the second man raped her vaginally.
    The first man called the second man "Chick" and said something
    about his "turn."
    While the rape was occurring, a van entered the parking lot
    and illuminated the area with its headlights such that the
    victim could see the second man.     This man then stood up and
    urinated on and around the victim.    The two men then ran from
    the parking lot with the van in pursuit.     The victim had trouble
    getting up because she kept slipping on the urine, but on doing
    so, she ran to a telephone booth and called her father.    The
    police were called and the victim went to the hospital, where
    evidence was collected and the victim was interviewed.     Two
    hours after the rape, the victim told police that she thought
    she had seen the second man before and that his name was Robert
    or "Chico."   Additionally, she provided the police with a
    physical description of the second man.     The police took the
    5
    Vincent Park was later charged with aggravated rape, but
    was found not guilty by reason of lack of criminal
    responsibility.
    5
    evidence, including the victim's clothing, when leaving the
    hospital.
    Later that morning, the victim went to the police station,
    looked through two books of photographs, and positively
    identified the defendant as the person who had raped her.     The
    police located the defendant at a local shelter at 6:45 A.M.
    Although the defendant had been scheduled to be at the shelter
    the previous night, he did not arrive until shortly before the
    police looked for him there.   The defendant fit the description
    of the second man provided by the victim.   At trial, the victim
    identified the defendant again.
    At trial, the parties stipulated that Mark Grant, a State
    police chemist, would testify to facts contained in his October,
    1983, report, that chemical tests conducted on a stain on the
    victim's underwear did not exclude the defendant as the source,
    but were inconclusive as to anything further.    The tests,
    conducted both on the stain and on a vaginal smear slide taken
    from the rape kit administered to the victim after the attack,
    were positive for the presence of a substance characteristically
    found in semen, but no sperm cells were found.
    The defendant was convicted and sentenced to a term of not
    more than twenty years or less than eighteen years in State
    prison.   On April 26, 1985, the Appeals Court affirmed the
    defendant's conviction, Commonwealth v. DiCicco, 19 Mass. App.
    6
    Ct. 1115 (1985).    After completing his sentence, the defendant
    was found to be a sexually dangerous person and was committed to
    the Nemansket Treatment Center at Bridgewater.
    2.   Postconviction proceedings.   In January, 2006, after
    the Superior Court clerk's office located the trial exhibits,6
    the defendant filed a motion for necessary access to test
    evidence for DNA, a motion for funds to do comparison DNA
    testing, and a request for discovery and access to the smear
    slide.    These motions were granted subject to the parties'
    filing a stipulation as to protocols for handling and testing
    the DNA evidence and subject to the availability of the smear
    slide.7
    In July, 2006, the defendant's motion for funds for a
    defense expert, Thomas Fedor of the Serological Research
    Institute, to observe the inventory and evidence assessment at
    the crime laboratory was granted.    Later that month, the
    Commonwealth filed a stipulation for release and testing of the
    evidence, wherein the parties agreed that portions of the
    victim's jeans and underpants would be released for testing.
    This stipulation was approved and Fedor was present in November,
    2006, when the clothing was examined at the crime laboratory.
    6
    Originally the Superior Court clerk's office in Middlesex
    County had indicated that the exhibits were "gone, destroyed."
    7
    The vaginal smear slide had been lost, and therefore was
    not available for testing in 2007 and 2008.
    7
    a.   Results of the crime laboratory DNA testing.   In
    December, 2006, the victim's clothing was examined at the crime
    laboratory.   No sperm cells or seminal fluid residue was
    detected in the stains on the victim's underpants.   Several
    stains were observed on the exterior and interior of the jeans,
    and sperm cells were detected in three of them.   Cuttings were
    then taken from these three stains (stains 9, 13, and 14).     Only
    stains 13 and 14 are relevant on appeal.8,9
    The crime laboratory10 extracted DNA from the above
    mentioned cuttings and performed short tandem repeat (STR)
    8
    The analysis of stain 9 by the crime laboratory resulted
    in a finding of "insufficient DNA" for comparison in both its
    sperm and nonsperm fractions. Carita does not offer an opinion
    as to stain 9.
    9
    The samples provided to the defense were subsequently
    tested by Orchard Cellmark (Cellmark), see infra.
    10
    Laboratories that analyze DNA samples for forensic
    casework purposes are required by the Quality Assurance
    Standards for Forensic DNA Testing Laboratories to "establish
    and follow documented procedures for the interpretation of DNA
    typing results and reporting." The Scientific Working Group DNA
    Analysis Methods (DNA working group), a group of individuals
    authorized by Congress to advise the Federal Bureau of
    Investigation on DNA testing, has promulgated interpretation
    guidelines that are generally accepted in the community of
    forensic DNA analysts. The crime laboratory has adopted the DNA
    working group's Y-STR guidelines, and analysts conducting Y-STR
    analysis are required to comply with these protocols. The DNA
    working group's guidelines recommend the establishment of
    certain thresholds in the interpretation of Y-STR DNA results.
    8
    testing/typing (specifically Y-STR testing)11 on stains 13 and
    14.   The Y-STR DNA testing is conducted first by subjecting the
    sample to a process of "differential extraction" which separates
    any sperm cells (sperm fraction) from epithelial cells (nonsperm
    fraction).   On stain 13, the crime laboratory concluded that the
    defendant was excluded as the source of the nonsperm fraction
    DNA,12 but that there was insufficient DNA for analysis in the
    sperm fraction, as the only result was a single "potential
    allele," falling below the threshold at which alleles can be
    positively identified, at Locus DYS456.13   As for stain 14, the
    11
    Short tandem repeat (STR) testing focuses on different
    places (loci) on the human genome where certain known sequences
    of DNA base pairs repeat themselves. The repeat sequences at a
    particular locus are called alleles. Analysts measure the
    number of times these repeat sequences occur in a forensic DNA
    sample to determine whether the sample matches the subject's DNA
    profile. Y-STR typing is a technique by which analysts separate
    male DNA from female DNA and focus only on the male fragment.
    12
    Alleles were identified ("called") at seven loci and
    potential alleles were identified at an additional four loci.
    13
    Consistent with DNA working group's Y-STR guidelines, the
    crime laboratory conducted validation studies to help establish
    certain thresholds for use in the interpretation of Y-STR DNA
    results. Based on the data generated in these validation
    studies, the crime laboratory established a "noise threshold,"
    which is "based on signal-to-noise analysis internally derived
    from empiric data." The noise threshold at the crime laboratory
    was established at fifty-five relative fluorescent units (RFUs).
    The crime laboratory also established a "call threshold," which
    is the level at which the laboratory would identify or report a
    peak as an allele given the strength of the result. The call
    threshold at the crime laboratory was established as three times
    the noise threshold, or 165 RFUs. Pursuant to the crime
    laboratory's protocol, peaks below the call level, but above the
    9
    crime laboratory concluded that there was a mixture of more than
    one male source in the nonsperm fraction, which yielded
    inconclusive results for comparison with the defendant's DNA,
    that is, he could not be included or excluded as one of the
    contributors.   With respect to the sperm fraction, there was
    insufficient DNA for analysis.
    b.   Motion for postconviction relief.   In November, 2007,
    the defendant filed a motion for postconviction relief, arguing
    that the results of the comparative DNA testing done by the
    crime laboratory exonerated him.   In March, 2008, the defendant
    filed a substitute motion for funds and access to do comparison
    DNA testing by the defendant's expert, or, in the alternative,
    for further testing by the Commonwealth and for funds for
    observation of such testing by the defendant's expert.14    On
    September 24, 2008, after a hearing, the judge allowed the
    defendant's motion for funds to have Cellmark take custody of
    noise level, are called "potential alleles," and are designated
    by an asterisk symbol and a number. Both called and potential
    alleles are "then checked by two DNA analysts to verify that the
    resulting peaks are found in the correct horizontal location
    ('binned' correctly) and are shaped correctly (have good 'peak
    morphology') and are not artifacts." The single potential
    allele detected in the crime laboratory's testing of the sperm
    fraction of stain 13 was approximately seventy RFUs, just over
    the noise threshold established by the laboratory, and
    significantly below the call threshold of 165 RFUs.
    14
    In support of this motion, the defendant submitted an
    affidavit of Thomas Fedor.
    10
    the useable samples from the crime laboratory and subject them
    to further DNA testing.
    With respect to stain 13, Cellmark concurred with the crime
    laboratory's conclusion as to the nonsperm fraction, that the
    defendant was excluded as the source.    With respect to the sperm
    fraction, where the crime laboratory testing had revealed a
    single potential allele, insufficient for analysis, Cellmark's
    testing detected no male DNA at all.    Cellmark's testing of the
    stain 14 sample also detected no male DNA in the sperm fraction,
    and concurred with the crime laboratory that the defendant could
    not be excluded as a contributor of the male DNA detected in the
    nonsperm sample.
    In March, 2010, the defendant filed a document entitled,
    "Submission of New Forensic Analysis and Motion for Immediate
    Relief," together with an affidavit of Carita.     The defendant
    had retained Carita to review the test data from the analyses of
    the crime laboratory and Cellmark.     In his affidavit, Carita
    stated an opinion that excluded the defendant as the source of
    DNA found in both stain samples (13 and 14) taken from the
    victim's jeans.    The Commonwealth filed an opposition to the
    defendant's motion along with an affidavit of Lemire.     In April,
    2010, the judge found that, notwithstanding certain limitations,
    the Carita affidavit stated an opinion that might be admissible
    in evidence.   Accordingly, she ordered an evidentiary hearing,
    11
    explaining that the defendant would have the burden of
    establishing both the admissibility of Carita's opinion and that
    any DNA evidence that would be admissible satisfied the standard
    for a new trial.
    3.   Evidentiary hearing.   A two-day evidentiary hearing was
    held, at which both Carita and Lemire testified15 and the
    laboratory reports were admitted in evidence.
    a.   Carita's testimony.    Consistent with his affidavit,
    Carita testified that the defendant was excluded as the donor of
    DNA extracted from the nonsperm fractions of stains 13 and 14.
    Although both laboratory reports and Lemire concurred that the
    defendant was excluded as the source of the nonsperm fraction of
    15
    At the hearing, the defendant did not call Fedor, his
    previous expert, as a witness, but stated that he was relying
    solely on the test results of the crime laboratory and Cellmark,
    along with Carita's testimony. Until he filed the Carita
    affidavit in March, 2010, the defendant had relied on an
    affidavit submitted by Fedor. Fedor did not personally analyze
    the DNA, but he had reviewed the test data from the crime
    laboratory. Fedor agreed with the crime laboratory that the
    defendant was excluded as the source of the DNA on the nonsperm
    fraction of stain 13. He disagreed, however, with the crime
    laboratory's conclusion that there was insufficient data to
    include or exclude the defendant as the source of the DNA from
    the nonsperm fraction of stain 14, concluding that the defendant
    was excluded as its source. Fedor did note that, "[a]dmittedly,
    there is the problem of 'extraneous DNA,'" but qualified this
    statement given his speculation that the cuttings were taken
    from the area of the victim's jeans that would have been
    "potentially soaking in the assailant's urine." Fedor did not
    address the crime laboratory's conclusion that the partial DNA
    profile obtained from stain 14 indicated the presence of more
    than one source. The record does not indicate that Fedor drew
    any conclusions regarding the sperm fractions of either cutting.
    12
    stain 13, only Carita testified that the defendant was also
    excluded as the donor of DNA extracted from the nonsperm
    fraction of stain 14.   Although he agreed with the crime
    laboratory (and Cellmark) that the DNA from the nonsperm
    fraction of stain 14 was a mixture from more than one male,
    Carita based his opinion of exclusion on the fact that "two
    possible genetic markers" identified by the crime laboratory as
    potential alleles at one location (DYS458) were inconsistent
    with the defendant's allele at that location.16   Additionally,
    Carita testified that the defendant also was excluded as the
    donor of the DNA extracted from the sperm fraction of stain 13.
    His opinion was based on the single potential allele, measured
    at approximately seventy relative fluorescent units (RFUs), at
    DYS456, far below the "call" threshold of 165 RFUs established
    by the crime laboratory.   See notes 12 and 
    13, supra
    .
    Carita acknowledged in his testimony that his opinion was
    not in accord with the crime laboratory's Y-STR interpretive
    guidelines, and offered no evidence that the Scientific Working
    Group DNA Analysis Methods (DNA working group) Y-STR guidelines
    explicitly permit an exclusion to be based on a single potential
    allele.   He contended, however, that his conclusions were
    nevertheless permissible under the provisions of the DNA working
    16
    Both the crime laboratory and Cellmark had concluded that
    there was insufficient data to render such a conclusion.
    13
    group's Y-STR guidelines, which state that "the interpretation
    of the results of casework is a matter of professional judgment
    and expertise . . . not every situation can or should be covered
    in a preset rule."   Carita went on to testify that he relied on
    the Connecticut State laboratory interpretive guidelines, which
    bind him in his consulting work, to form his opinion, but these
    were not introduced in evidence.
    b.   Motion judge's ruling.    After hearing, the judge ruled
    that, given the limited data from the low-level DNA procured
    from the victim's clothing, Carita's opinions with respect to
    the sperm fraction of stain 13 and the nonsperm fraction of
    stain 14, which were based exclusively on potential alleles,
    were not sufficiently reliable to be placed before a jury.     With
    respect to the sperm fraction of stain 13, the judge found that
    Carita cited no authority for the proposition that an exclusion
    may be based on a single potential allele in the absence of any
    other data, and that the potential allele on which he relied did
    not meet "the requirements of the laboratory's calling
    threshold, which gives absolute confirmation that a genetic
    marker is DNA and not a possible artifact."   The judge also
    found that although Carita agreed that the detected DNA in the
    nonsperm fraction of stain 14 was a mixture, he cited no
    authority for the proposition that an exclusion may be based on
    two potential alleles at one locus in such a mixed sample where
    14
    the possibility of stutter17 cannot be eliminated.   Although the
    judge acknowledged that it is permissible to use potential
    alleles in the interpretation of a DNA profile, "[i]n this case
    . . . given the minimal amount of DNA, Carita is not using
    potential alleles to interpret results.   His opinions are based
    solely on peaks identified as potential alleles in the context
    of very limited data obtained from low-level DNA."18
    After concluding that Carita's opinions with respect to the
    sperm fraction of stain 13 and the nonsperm fraction of stain 14
    would not be admitted in evidence, she went on to find that the
    newly discovered DNA evidence which would be admissible lacked
    the materiality, weight, and significance necessary to
    demonstrate that it would likely have been a real factor in the
    jury's deliberations.
    Discussion.   "Motions for a new trial are addressed to the
    'sound discretion' of the trial judge."   Commonwealth v.
    DiBenedetto, 
    458 Mass. 657
    , 663-664 (2011), citing Commonwealth
    v. De Christoforo, 
    360 Mass. 531
    , 542 (1971).   See also Mass. R.
    17
    Stutter, "a very common artifact," is a byproduct of the
    process used to amplify DNA and will result in peaks that occur
    before and after a real peak. Accordingly, stutter peaks may
    mask true peaks.
    18
    In making her findings, the judge pointed out that the
    findings in the report of Cellmark, an independent laboratory
    hired by the defendant, were consistent with the crime
    laboratory findings in all material respects, and both stood in
    stark contrast to Carita's opinion as to the adequacy of the
    data to make an exclusion.
    15
    Crim. P. 30 (b), as appearing in 
    435 Mass. 1501
    (2001).       "Judges
    are to apply the standard set out in Mass. R. Crim. P. 30 (b)
    rigorously," and "grant such a motion only if it appears that
    justice may not have been done" (quotations and citations
    omitted).    Commonwealth v. Fanelli, 
    412 Mass. 497
    , 504 (1992).
    "[A]n appellate court will examine the motion judge's conclusion
    only to determine whether there has been a significant error of
    law or other abuse of discretion."     
    DiBenedetto, 458 Mass. at 664
    , quoting Commonwealth v. Wolinski, 
    431 Mass. 228
    , 235
    (2000).
    1.      The exclusion of Carita's opinion.   In 
    Lanigan, 419 Mass. at 25-26
    , we adopted, in part, the standard for the
    admissibility of expert testimony delineated by the United
    States Supreme Court in Daubert v. Merrell Dow Pharmaceuticals,
    Inc., 
    509 U.S. 579
    (1993).     In so doing, we held that "a
    proponent of scientific opinion evidence may demonstrate the
    reliability or validity of the underlying scientific theory or
    process by some other means, that is, without establishing
    general acceptance,"     
    Lanigan, supra
    at 26, as "the touchstone
    of admissibility is reliability, and not necessarily general
    acceptance within the scientific community."     Commonwealth v.
    Vao Sok, 
    425 Mass. 787
    , 796 (1997), quoting Commonwealth v.
    Sands, 
    424 Mass. 184
    , 185-186 (1997).     However, we noted that,
    "in most cases general acceptance will be the significant, and
    16
    'often the only, issue.'"    Canavan's Case, 
    432 Mass. 304
    , 310
    (2000), quoting 
    Lanigan, supra
    .     Accordingly, "a party seeking
    to introduce scientific evidence may lay an adequate foundation
    either by establishing general acceptance in the scientific
    community or by showing that the evidence is reliable or valid
    through an alternate means."    Canavan's 
    Case, supra
    .
    Under Daubert-Lanigan, the motion judge, in her role as
    gatekeeper, "has a significant function to carry out in deciding
    on the admissibility of a scientific expert's opinion."
    
    Lanigan, 419 Mass. at 25
    .    Conclusions based on personal
    observation or clinical experience are subject to this analysis.
    Canavan's 
    Case, 432 Mass. at 313
    .     The expert's opinion must
    "have a reliable basis in the knowledge and experience of his
    discipline," 
    Daubert, 509 U.S. at 592
    , and the motion judge must
    assess "whether the reasoning or methodology underlying [an
    expert witness's] testimony is scientifically valid and whether
    that reasoning or methodology is properly applied to the facts
    in issue."    
    Lanigan, supra
    at 26, quoting Daubert, supra at 592-
    593.
    Accordingly, if the process or theory underlying an
    expert's opinion lacks sufficient reliability or an expert
    cannot provide a reliable factual basis for his conclusions, the
    trial judge must exclude the opinion from reaching the trier of
    fact.    
    Lanigan, 419 Mass. at 25-26
    .   See Canavan's Case, 
    432 17 Mass. at 315
    .19    The defendant, as the proponent of the expert
    testimony at issue, has the burden to establish that Carita's
    opinion is reliable.     See Commonwealth v. Sliech-Brodeur, 
    457 Mass. 300
    , 328 n.41 (2010), citing Canavan's 
    Case, 432 Mass. at 314
    .    We review a judge's determination to admit or exclude
    expert testimony under Daubert-Lanigan for an abuse of
    discretion.    Commonwealth v. Vasquez, 
    462 Mass. 827
    , 844 (2012).
    Commonwealth v. Pytou Heang, 
    458 Mass. 827
    , 844 (2011).      As we
    have held previously, "the admissibility of DNA test results
    should be determined on a case-by-case basis."      Commonwealth v.
    Mathews, 
    450 Mass. 858
    , 871 (2008), citing Commonwealth v.
    Curnin, 
    409 Mass. 218
    , 222 (1991).20
    a.   Stain 13.   The defendant argues that Carita's opinion
    regarding the sperm fraction of stain 13 is admissible for a few
    reasons.     First, he contends that the opinion meets the Daubert-
    Lanigan standard as it is "based on reliable data from which
    [Carita] drew a logical conclusion."      The defendant notes that
    the motion judge never found that the potential allele found in
    19
    See Mass. G. Evid. § 702 (2014) (expert opinion may be
    given if "[a] the testimony is based upon sufficient facts or
    data, [b] the testimony is the product of reliable principles
    and methods, and [c] the witness has applied the principles and
    methods reliably to the facts of the case").
    20
    "[A] judge's determination on the reliability of
    scientific testimony is no different from other evidentiary
    decisions by a trial judge that are reviewed on appeal under an
    abuse of discretion standard of review." Canavan's Case, 
    432 Mass. 304
    , 311 (2000).
    18
    the sperm fraction of stain 13 was unreliable.    Further, both
    Carita and Lemire testified that potential alleles were used in
    the work of DNA analysts.    Both individuals additionally agreed
    that the potential allele was correctly designated and that it
    had the hallmarks of correct binning and good peak morphology.
    See note 
    13, supra
    .    Moreover, the potential allele occurred at
    a smaller locus, making it more efficiently amplified and, the
    defendant contends, reliable.    The defendant argues that
    excluding Carita's opinion because of factors such as potential
    DNA degradation21 is improper, as both experts agreed that
    degradation would not change the defendant's allele at DYS456.
    Second, the defendant argues that Carita's opinion was
    reasonable, and that Carita's reliance on a single potential
    allele is "merely application of accepted methodology to a
    specific context."    He contends that Carita did follow the Y-STR
    interpretation guidelines set forth by the DNA working group, as
    promulgated in January, 2009, which state that interpreting
    evidence is a matter of "professional judgment and expertise"
    and "[n]ot every situation can or should be covered by a preset
    rule."    Further, the defendant contends that Carita's conclusion
    21
    As the motion judge found, degradation "relates to the
    DNA molecule breaking up . . . over time," or due to exposure to
    certain other factors. A proper environment for DNA storage is
    in breathable material (e.g., paper) and in a cool, dark, dry
    environment. Degradation of DNA can occur as a result of
    ultraviolet light, chemicals, or microbes, in addition to
    improper packaging and handling.
    19
    aligns with § 1.1.1.1. of the DNA working group's Y-STR
    guidelines, which states that the "analytical thresholds are
    defined as the minimum and maximum intensity thresholds between
    which data are reliable for use in allele designations."
    Accordingly, he contends that the lack of a specific DNA working
    group guideline governing exclusion on single potential alleles
    is of no import.
    Last, the defendant argues that the motion judge
    misunderstood her gatekeeping role under Daubert-Lanigan.     He
    contends that the motion judge's issue with Carita's
    interpretation of the data and her concerns over factors such as
    possible degradation ought to have gone only to the opinion's
    weight, rather than its admissibility, and remained a question
    for a jury to determine.
    After reviewing the record before the judge below, we
    cannot say that she abused the discretion afforded to her under
    Daubert-Lanigan in excluding Carita's testimony.   Carita's
    opinion that the defendant was excluded as the contributor of
    the sperm fraction of stain 13 was based solely on a single
    below-threshold peak.   He acknowledged that this potential
    allele did not meet the crime laboratory's calling threshold,
    which would have provided "absolute confirmation that a genetic
    marker is DNA and not a possible artifact," but nevertheless was
    20
    "probably true" DNA.22   Although it is undisputed that such
    potential alleles may be used for interpretational purposes
    along with other data when examining an individual's DNA
    profile, it was not an abuse of discretion to find that, in the
    absence of any authority substantiating Carita's opinion, a
    single potential allele without any other data is not enough to
    exclude an individual.     As Lemire testified, "[T]here's just not
    enough data . . . to generate any comparison . . . ."
    Based on the record on appeal, Carita provided virtually no
    support for his opinion except to testify that the DNA working
    group does not explicitly prohibit this practice and that he
    once before had rendered a similar exclusion opinion based on a
    single potential allele.    Aside from this testimony, the
    defendant offered no evidence to establish that Carita's opinion
    was generally accepted by the relevant scientific community or
    otherwise was sufficiently reliable.    Carita cited to no
    scientific authority, in either his affidavit or in his hearing
    22
    The motion judge appears to have erred in her finding
    that Carita admitted that he had not complied with DNA working
    group guidelines in reaching his opinion. Although it is
    accurate that Carita did not comply with the crime laboratory's
    protocols that had been promulgated in accord with the DNA
    working group's advice that each laboratory "prepare guidelines
    for formulating conclusions resulting from comparisons of
    evidentiary samples and known reference samples," see § 4.1 of
    the DNA working group's Y-STR guidelines, he did not violate any
    explicit DNA working group provision. However, this fact does
    not change our over-all assessment that, for a myriad of other
    reasons, the judge did not abuse her discretion in ruling
    Carita's opinion inadmissible.
    21
    testimony, to support his ultimate conclusion, instead relying
    solely on his "judgment and expertise."23   Nor did the defendant
    supply the judge with written guidelines for Carita's laboratory
    in Connecticut or any other laboratory which supported the
    reliability of Carita's opinion.   See Canavan's 
    Case, 432 Mass. at 315
    , quoting Kumho Tire Co. v. Carmichael, 
    526 U.S. 137
    , 157
    (1999) (no rule requires court "to admit opinion evidence that
    is connected to existing data only by the ipse dixit of the
    expert").
    Carita pointed to no error in Lemire's analysis and did not
    challenge Cellmark's conclusions that it found no DNA at all in
    the sperm fraction of stain 13.    Although it is accurate that
    Lemire agreed that the potential allele in question was likely
    real human DNA, she explained that, under the DNA working group
    and the crime laboratory's protocols, she could not confirm this
    conclusion, as the potential allele registered below the call
    threshold and she had no other results to interpret.   She
    explained that although the peak in question resembled real DNA,
    it could have just been noise given its registration below the
    23
    In support of Carita's opinion, the defendant's brief
    cites to a single article entitled "DNA for the Defense Bar,"
    issued by the Department of Justice's National Institute of
    Justice (2012), which was not before the motion judge and to
    which the Commonwealth objects. The defendant neither argues
    that this publication qualifies as a learned treatise nor that
    it would have been admissible at the evidentiary hearing. As
    such, it does not affect our calculus as to whether the judge
    abused her discretion in deeming Carita's opinion inadmissible.
    22
    call threshold.     Further, while acknowledging that a potential
    allele may be used for interpretation, Lemire repeatedly
    testified that in order to use potential alleles below threshold
    in her analysis she would need additional information at any
    given profile in order to utilize that information for an
    interpretation.24     This was all the more convincing to the judge
    given Lemire's testimony that the tested sample is "low template
    DNA," and it is possible that inhibition25 and degradation may
    have been factors in the sample.26
    b.   Stain 14.    The defendant also argues that Carita's
    opinion regarding the nonsperm fraction of stain 14 ought to be
    admissible.   Testing indicated that this fraction was likely a
    24
    The defendant takes issue with the fact that Lemire used
    alleles below threshold to support a conclusion of inclusion in
    her testimony in a different case. However, there, unlike here,
    Lemire had "additional information beyond simply . . . a
    potential allele below threshold" to aid her analysis. The
    judge concluded that the cases were sufficiently dissimilar such
    that Lemire's conclusions are not inconsistent.
    25
    As the motion judge found, inhibition "relates to the
    ability to generate an STR profile." In the quantification
    system, there is an internal positive control that is used as an
    indicator as to "whether inhibitors or chemicals or anything
    intrinsic to the DNA . . . sample may be compromising or not
    allowing the method to work effectively." However, even where
    inhibition is not detected at the quantification stage, it may
    be present at different sites and affect the analysis.
    26
    Although Carita testified that he saw no evidence of
    these factors in the sample, he also qualified his testimony to
    state that the sample involved a very small amount of DNA, so he
    could see no appearance of inhibition, and "the profile's too
    low to determine whether there could or could not have been
    degradation."
    23
    mixture of DNA from more than one male.   Data were retrieved at
    just four loci and only two alleles (out of a potential
    seventeen or eighteen) were called.   Of these two called
    alleles, one at DYS393 matched the defendant, while the other at
    DYS389I was inconsistent with his profile.    Two other potential
    alleles (one at DYS389I and the other at DYS391) were also
    consistent with the defendant.   Of chief significance to
    Carita's opinion was the identification of two additional
    potential alleles at another locus, DYS458, which did not match
    the defendant.   Lemire and Carita agreed that the presence of
    these two potential alleles at the same location likely
    indicated a mixture of DNA from more than one source.     Carita,
    however, inferred from these two potential alleles that the
    defendant definitively could be excluded as the contributor of
    the nonsperm fraction of stain 14.    Lemire, on the other hand,
    testified that the data obtained were insufficient for
    comparison.   Cellmark's test results agreed with Lemire's
    conclusion.
    As with the sperm fraction from stain 13, discussed above,
    we cannot say that it was an abuse of discretion for the judge
    to rule Carita's opinion inadmissible.    As an initial matter,
    the two potential alleles at DYS458 that form the basis of
    Carita's opinion were just fifteen RFUs above the crime
    laboratory's noise threshold.    Lemire testified that sufficient
    24
    DNA was not found such that one could eliminate the possibility
    of "stutter" from this mixed sample.27   She explained that the
    two potential alleles in question, at just fifteen RFUs, gave
    rise to the possibility of a peak which would be consistent with
    the defendant's known DNA profile at DYS458 in a "stutter"
    position.28   She explained that if there were sufficient DNA in
    the sample, which there was not, an analyst could determine
    whether there was DNA present from something other than a
    stutter artifact.    However, Lemire explained that here the
    defendant could not be excluded because the data were too
    limited to evaluate whether there was something more than
    stutter present.29   Carita testified that "there was no stutter
    available for evaluation," as it was a "low-level sample."
    The appellate record is devoid of any reliable authority to
    support Carita's conclusion that an individual can be excluded
    27
    In mixed samples, stutter and alleles can overlap,
    thereby complicating interpretation.
    28
    Stutter occurs when, during the amplification process, a
    fragment one repeat unit smaller or larger than the true allele
    is produced. As a result, stutter generates a peak that is
    actually one repeat unit off from the main peak. A stutter
    artifact of a 15 allele (such as that of the defendant at the
    DYS458 locus) could appear at a 16 allele because of the stutter
    effect. See note 
    17, supra
    .
    29
    Lemire testified that, according to the crime
    laboratory's Y-STR guidelines, had there been peaks present
    above the call threshold at this loci she would have been able
    to evaluate whether the potential alleles at fifteen RFUs were
    more than just stutter.
    25
    as a donor based on these two potential alleles that (1) are in
    a low-level mixed sample, (2) register merely fifteen RFUs above
    the noise threshold, and (3) may represent a stutter peak.     He
    does not point to any DNA working group or crime laboratory
    guideline or other scientific authority that permits his
    conclusion.   Carita did not merely use these potential alleles
    to aid in his over-all interpretation of a DNA profile, but
    instead he made below-threshold peaks the sole basis for his
    opinion.
    2.     Admissible evidence as factor in jury deliberations.
    We also must consider whether the defendant has established that
    the DNA evidence that is admissible casts meaningful doubt on
    the justice of his conviction.   See Commonwealth v. Grace, 
    397 Mass. 303
    , 305 (1986); Mass. R. Crim. P. 30 (b) ("trial judge
    . . . may grant a new trial at any time if it appears that
    justice may not have been done").   See also Commonwealth v.
    Cintron, 
    435 Mass. 509
    , 516 (2001), overruled on other grounds
    by Commonwealth v. Hart, 
    455 Mass. 230
    (2009); Commonwealth v.
    Pike, 
    431 Mass. 212
    , 218 (2000).
    The relevant question is not whether the verdict would have
    necessarily been different, but "whether the new evidence would
    probably have been a real factor in the jury's deliberations."
    
    Grace, 397 Mass. at 306
    .    Additionally, the new evidence must
    demonstrate such materiality, weight, and significance that the
    26
    motion judge could find that "there is a substantial risk that
    the jury would have reached a different conclusion had the
    evidence been admitted at trial."    
    Id. As rule
    30 (b) motions
    are attacks on final decisions, they are "granted only in
    extraordinary circumstances," Commonwealth v. Comita, 
    441 Mass. 86
    , 93 (2004), and the defendant has the burden of producing a
    "credible reason" to reverse the final decision that "outweighs
    the risk of prejudice to the Commonwealth."     Commonwealth v.
    Lopez, 
    426 Mass. 657
    , 662 (1998), quoting 
    Fanelli, 412 Mass. at 504
    .
    Both the crime laboratory and Cellmark agreed that the
    defendant was excluded as the source of the DNA recovered from
    the nonsperm fraction of stain 13.   The defendant argues that
    this stain must have been deposited by the assailant's urine at
    the time of the attack, by virtue of the victim's trial
    testimony that the assailant urinated "on and around me" and
    that she slipped in urine while attempting to stand.30
    Accordingly, the defendant argues that because these cells
    30
    Although urea, a substance typically found in urine, was
    not detected in the sample, the defendant argues that this
    substance might have dissipated in the intervening twenty-three
    years between when the pants were collected in evidence and when
    they were submitted for DNA testing. We note that this is
    possible, as a crime laboratory's chemist averred in her report
    that the failure to detect semen and urine is unremarkable as
    such fluids do not have cell walls and break down more easily
    than epithelial cells.
    27
    indisputably do not belong to him, he could not have been the
    assailant.
    However, as noted by the judge, there is no scientific
    method of ascertaining whether these cells were deposited by the
    assailant or by any one of the many individuals who handled the
    evidence after the commission of the crime.    The pants in
    question were taken from the victim at the hospital, turned over
    to the police, and admitted in evidence at trial.    For over
    twenty years the evidence was indisputably stored in plastic
    bags, an environment incapable of protecting against
    contamination.31   The defendant's argument that the epithelial
    cells present in stain 13 necessarily came from the assailant's
    urine is a statement of conjecture, at best.
    It remains the defendant's burden to demonstrate the
    importance of newly available evidence, see 
    Grace, 397 Mass. at 306
    , and there is simply no way of determining when and under
    what circumstances the male DNA obtained from the nonsperm
    fraction of this stain was deposited.   Lemire specifically
    testified that she was unable to draw any conclusions as to the
    time or manner by which the DNA was deposited and she had no
    scientific way of assessing whether the evidence had been
    31
    The crime laboratory's DNA Y-STR report states,
    "[e]xtraneous DNA may be present on common articles such as
    clothing, shoes, etc. This extraneous DNA often manifests
    itself as a low level minor male contributor in a DNA result,
    and may have no probative value in a case."
    28
    contaminated prior to its arrival at the crime laboratory.
    Accordingly, the judge could not determine whether the exclusion
    of the defendant as the contributor of this DNA had any
    significant probative value, thereby diluting the defendant's
    argument of materiality and undermining claims that the jury
    would have reached a different conclusion had the evidence been
    admitted at trial.
    In sum, the newly available, admissible evidence would have
    shown that (1) the DNA, if any, contained in the sperm cells of
    both stains and the nonsperm cells of stain 14 were insufficient
    to either include or exclude the defendant as their donor; and
    (2) it is not possible to determine the significance of the fact
    that the defendant was excluded as a source of the nonsperm
    cells in stain 13.   We agree with the judge that this evidence
    would not be capable of casting meaningful doubt on the jury's
    verdict that the defendant was the perpetrator of the rape.
    3.    Additional expert funds.   The defendant first filed a
    motion for funds to do comparison DNA testing in January, 2006.
    In May of that year, the motion was granted in the amount of
    $4,000.   Subsequently, in July, 2006, the defendant filed a
    motion for funds in the amount of $5,000 for his defense expert
    at the time (Fedor) to observe the inventory and assessment of
    evidence at the crime laboratory.    This motion was granted.
    29
    Nearly two years later, in March, 2008, the defendant filed
    a substitute motion for funds and access to do comparison DNA
    testing by the defendant's expert, or, in the alternative, for
    further testing by the Commonwealth and for funds for
    observation of such testing by the defendant's expert.     A second
    motion for funds was filed in September, 2008, and the judge
    permitted the defendant's motion in the amount of $6,575 to have
    Cellmark take custody of usable samples from the crime
    laboratory and subject them to independent DNA testing.
    In October, 2009, the defendant moved for funds in the
    amount of $5,500 for the attendance of Fedor and "a like amount"
    for the attendance of a representative from Cellmark at an
    evidentiary hearing.   As of March, 2010, the motion judge did
    not believe, based on the record as it existed (which included
    an affidavit submitted by Fedor as well as reports from both the
    crime laboratory and Cellmark), that the defendant was entitled
    to an evidentiary hearing on his motion for a new trial.
    Subsequently, the defendant filed a document entitled
    "Submission of New Forensic Analysis and Motion for Immediate
    Relief," alongside the aforementioned Carita affidavit.     The
    defendant had not sought court approval to retain Carita, and
    according to his affidavit, Carita had reviewed test data from
    the crime laboratory's analysis on a voluntary basis up until
    that point.   The Commonwealth filed an opposition, but in April,
    30
    2010, the judge found that, notwithstanding certain limitations,
    the Carita affidavit stated an opinion that might be admissible
    in evidence.   Accordingly, the motion judge granted an
    evidentiary hearing, ordering the parties to "explore the
    possibility of minimizing the cost to the Commonwealth" by
    taking video testimony of Fedor and a Cellmark representative.
    The defendant filed, and the judge allowed, a motion for
    funds for the attendance of an expert witness in the amount of
    $4,500 for Carita to attend the evidentiary hearing.    In his
    motion, the defendant made clear that this request was "an all
    inclusive authorization, covering preparation, travel, and court
    time."   The hearing took place on July 9 and 23, 2010, at which
    both Carita and Lemire testified.   As discussed above, the
    motion judge ultimately found that Carita's opinions would not
    be admissible at trial.
    Approximately one year later, in May, 2011, the defendant
    sought additional funds to cover the remainder of Carita's bill,
    explaining that the original funds sought constituted an
    underestimate based on an expected one-day evidentiary hearing.
    The motion judge denied the motion without prejudice to renew.
    On September 1, 2011, the defendant filed a renewed motion for
    funds with an accompanying affidavit detailing Carita's dates of
    service, work performed, and time spent traveling.     The
    defendant asserted that Carita was retained because the cost of
    31
    transporting Fedor and an expert from Cellmark was
    "substantial," and counsel had been "unsuccessful" in making
    video conferencing arrangements.   The motion judge denied this
    motion as well, basing her decision on the defendant's failure
    to seek prior approval to retain Carita and her view that
    Carita's testimony was unreliable, inadmissible, and put forth
    solely "to supplement an inadequate record."
    Rule 30 (c) (5) of the Massachusetts Rules of Criminal
    Procedure, as appearing in 
    435 Mass. 1501
    (2001), and as
    explained by the Reporters' Notes to Rule 30, Mass. Ann. Laws
    Court Rules, Rules of Criminal Procedure, at 1710-1711
    (LexisNexis 2014), "gives judges discretion to allow for the
    payment of costs associated with the preparation and
    presentation of a new trial motion" (quotations and citation
    omitted).   Commonwealth v. Mitchell, 
    438 Mass. 535
    , 555, cert.
    denied, 
    539 U.S. 907
    (2003).   See Commonwealth v. Evans, 
    439 Mass. 184
    , 204, cert. denied, 
    540 U.S. 923
    , and cert. denied,
    
    540 U.S. 973
    (2003).   Further, where an indigent defendant seeks
    to obtain additional evidence in connection with a motion for
    postconviction relief that would likely raise a meritorious
    defense warranting a new trial, the judge has discretion to
    grant a motion for funds to hire an expert.    See 
    Mitchell, 438 Mass. at 555
    .   A judge considering such a motion for expert
    funds must consider "not only the potential admissibility of the
    32
    expert's testimony and its cost, but also the 'desirability or
    necessity' of the testimony to the requesting party's case."
    Commonwealth v. Zimmerman, 
    441 Mass. 146
    , 153 (2004), quoting
    Commonwealth v. Lockley, 
    381 Mass. 156
    , 161 (1980).
    The judge likely factored the above considerations into her
    assessment when granting the initial $4,500 for Carita to appear
    and testify at the evidentiary hearing, given that she ordered
    the hearing only after receiving Carita's affidavit and finding
    that Carita presented an opinion that "might be admissible."     At
    that point, the motion judge had before her the substance of
    Carita's testimony, which did not vary at the hearing.
    Although the judge would have had discretion to deny the
    defendant's initial request for funds, see 
    Zimmerman, 441 Mass. at 152-153
    , her initial approval strongly supports the inference
    that she deemed Carita's services to be reasonably necessary.
    And although the defendant did not seek explicit permission to
    retain Carita, the judge implicitly provided such permission
    when granting $4,500 for Carita to appear and testify at the
    evidentiary hearing.
    Accordingly, it appears that the judge predicated the grant
    of additional expert funds on whether she ultimately agreed with
    the substance of Carita's opinion, and when denying the
    defendant's renewed motion for funds, she explicitly stated that
    "[h]ad the Court realized the extent to which the opinions of
    33
    Mr. Carita that led to the evidentiary hearing were not based on
    any accepted or reliable scientific methodology, the Court would
    not have allowed" the original funds for Carita's attendance and
    testimony.
    Carita adequately documented the services he performed and
    the time spent assisting the defendant's case.    He testified on
    behalf of the defendant over the course of an (unanticipated)
    two-day evidentiary hearing and assisted defense counsel in
    drafting proposed findings of fact.    Additionally, although the
    judge took issue with the fact that the defendant did not obtain
    explicit permission to retain Carita, up until the point at
    which the defendant sought and the judge granted funds, Carita
    had provided his services pro bono.    Once the judge granted the
    funds requested by the defendant so that Carita could attend the
    evidentiary hearing, it was not unreasonable for the defendant
    to believe he had the judge's permission to retain Carita.
    Although the defendant's initial request assured the judge it
    would be an "all inclusive authorization," the evidentiary
    hearing lasted one day longer than anticipated.
    It was only in hindsight, after her ultimate finding on the
    admissibility of his opinion, that the judge denied additional
    funds.   This is impermissible.   See 
    Zimmerman, 441 Mass. at 152
    -
    153 (judge should consider not only potential admissibility of
    expert testimony, but also "desirability or necessity" to the
    34
    requesting party's case).   See also 
    Lockley, 381 Mass. at 161
    .
    Accordingly, it was an abuse of discretion to deny the
    defendant's supplemental request to pay Carita for additional
    services rendered.32
    Conclusion.   The denial of the defendant's motion for a new
    trial is affirmed and the denial of supplemental expert funds is
    reversed.   The case is remanded for further proceedings
    consistent with this opinion.
    So ordered.
    32
    It would have been permissible for the judge to deny the
    request for additional funds if they were not justified because
    the additional expenses had been foreseeable (but not approved
    in advance) or because the amount was unreasonably high for the
    services rendered.