Court Opinion

ID: 4547794
Source: CourtListenerOpinion
Date Created: 2020-07-13 15:00:14.107487+00
Date Added: 2024-06-11T12:55:06.546030
License: Public Domain

18-3800-cr
     USA v. Jones

 1                            UNITED STATES COURT OF APPEALS

 2                                  FOR THE SECOND CIRCUIT

 3                                               -----

 4                                        August Term, 2019

 5   (Argued: April 2, 2020                                              Decided: July 13, 2020)

 6                                      Docket No. 18-3800-cr

 7   _________________________________________________________

 8   UNITED STATES OF AMERICA,

 9                                                     Appellee,
10
11                                      - v. -

12   DEAN JONES, a/k/a "Korrupt," a/k/a "Blacko," a/k/a
13   "Christopher C. Walker,"
14                                                  Defendant-Appellant.*
15   _________________________________________________________

16   Before: KEARSE, CABRANES, and SACK, Circuit Judges.

17

     *     The Clerk of Court is instructed to amend the official caption to
           conform with the above.
 1          Appeal from a judgment of the United States District Court for the Southern

 2   District of New York, Vernon S. Broderick, Judge, convicting defendant, after bifurcated

 3   trials, of conspiracy to distribute and possess with intent to distribute narcotics, in

 4   violation of 21 U.S.C. §§ 846 and 841(b)(1)(A); Hobbs Act robbery and Hobbs Act

 5   conspiracy, in violation of 18 U.S.C. § 1951; and possession of a firearm, which had

 6   been    discharged,     in furtherance of the robbery,          in violation    of    18   U.S.C.

 7   §§ 924(c)(1)(A)(iii).    Defendant principally challenges the admission, at his trial on the

 8   Hobbs Act and firearm counts, of expert testimony based on the Forensic Statistical

 9   Tool method of DNA analysis used by New York City's Office of the Chief Medical

10   Examiner.    As to the narcotics trial, defendant challenges the court's rejection of his

11   proposed instruction on multiple conspiracies and its denial of his motion for a new

12   trial based on newly discovered evidence as to the credibility of a government witness.

13   Concluding that the district court properly applied Daubert principles, and finding no

14   error in the court's instructions or its denial of a new trial, we affirm the judgment.

15                  Affirmed.

16                           THOMAS McKAY, Assistant United States Attorney, New
17                               York, New York (Geoffrey S. Berman, United States
18                               Attorney for the Southern District of New York,
19                               Anna M. Skotko, Assistant United States Attorney,
20                               New York, New York, on the brief), for Appellee.

                                                      2
 1                       IRVING COHEN, New York, New York, for
 2                             Defendant-Appellant.

 3   KEARSE, Circuit Judge:

 4                Defendant Dean Jones appeals from a judgment entered in the United

 5   States District Court for the Southern District of New York following bifurcated jury

 6   trials before Vernon S. Broderick, Judge, convicting him on one count of conspiracy to

 7   distribute and possess with intent to distribute five kilograms and more of cocaine,

 8   280 grams and more of cocaine base, and one kilogram and more of heroin, in violation

 9   of 21 U.S.C. §§ 846 and 841(b)(1)(A); one count of Hobbs Act robbery and one count

10   of Hobbs Act conspiracy, in violation of 18 U.S.C. § 1951; and one count of possession

11   of a firearm, which was discharged, in furtherance of the robbery, in violation of 18

12   U.S.C. §§ 924(c)(1)(A)(iii); and sentencing him principally to a total of 312 months'

13   imprisonment, to be followed by five years of supervised release.     On appeal, Jones

14   contends principally that at his trial on the Hobbs Act and firearm counts, the district

15   court abused its discretion in admitting DNA evidence and expert testimony based on

16   the Forensic Statistical Tool method of DNA analysis used by New York City's Office

17   of the Chief Medical Examiner.    As to the narcotics trial, Jones challenges the court's

                                                3
 1   rejection of his proposed instruction on multiple conspiracies and its denial of his

 2   motion for a new trial based on newly discovered evidence as to the credibility of a

 3   government witness.      Concluding that the district court properly applied the principles

 4   established in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), and

 5   finding no merit in Jones's other contentions, we affirm the judgment.

 6                                        I. BACKGROUND

 7                 In the operative superseding indictment ("Indictment"), Jones was charged

 8   in five counts:    one count of conspiring to distribute and possess with intent to

 9   distribute heroin, cocaine, and cocaine base from in or about 2011 through in or about

10   August 2016, and one count of possession of a firearm in furtherance of the narcotics

11   conspiracy (collectively the "Narcotics Charges"); and one count each of Hobbs Act

12   conspiracy and Hobbs Act robbery on or about December 21, 2012, along with one

13   count of possession of a firearm, which was discharged, in furtherance of the Hobbs

14   Act crimes (the "Robbery Charges").        Six other persons were named as codefendants

15   with Jones in the Narcotics Charges; Jones was the only named defendant in the

                                                    4
 1   Robbery Charges.

 2                 The district court severed the Narcotics Charges from the Robbery

 3   Charges. In his trial on the Narcotics Charges (see Part III below), Jones was convicted

 4   on the conspiracy count but was acquitted on the firearm charge related to that

 5   conspiracy.    The proceedings relevant to Jones's challenges to the         conspiracy

 6   conviction are summarized in Part III.        The evidence relevant to his trial on the

 7   Robbery Charges, taken in the light most favorable to the government, included the

 8   following.

 9   A. The Robbery Charges

10                 Jones was arrested by New York City Police Department ("NYPD") officers

11   in June 2013, and was indicted on the federal robbery and firearm charges in 2015 and

12   2016, in connection with a robbery at a restaurant in the Bronx in December 2012.

13   There was security camera video of the robbery, and other evidence, including DNA

14   evidence, to indicate that Jones was one of the robbers.   The only issue raised on this

15   appeal to challenge Jones's convictions on the Robbery Charges is whether a portion

16   of that DNA evidence was properly admitted.

                                                   5
 1          1. The Events

 2                 After midnight on December 21, 2012, Jones and an accomplice, both

 3   wearing masks and blue latex gloves, entered a restaurant in the Bronx; Jones was

 4   carrying a gun, and his accomplice picked up a pair of kitchen scissors.         A security

 5   camera video showed the two men brandishing their weapons, collecting cash from

 6   the register, and taking money and cell phones from customers.        When one customer

 7   attempted to remove money from the wallet in his pocket, Jones punched him in the

 8   head and shot him in the leg.

 9                 When the robbers attempted to flee the scene, they were seen by NYPD

10   officers. Jones fired a shot, hitting a parked car; he then discarded the gun (which was

11   retrieved by another accomplice, who had been outside the restaurant serving as a

12   lookout, and who fled, unnoticed by the officers).      The scissors-wielding robber was

13   apprehended quickly. Jones had run in another direction and escaped the scene.

14                 Jones was eventually arrested and charged, as indicated above.           The

15   government's evidence that Jones had been the gun-wielding robber on December 21,

16   2012, included (a) cell site location data showing that the movements of Jones's

17   cellphone tracked the movements of the robbers; (b) Jones's proffer of an alibi, which

                                                  6
 1   the out-of-state relative he claimed to have been visiting at the time of the robbery

 2   would not corroborate, and which was inconsistent with the cell site evidence as to the

 3   movements of Jones's cellphone; and (c) testimony by cooperating witness Steven

 4   Christopher, who testified that he and Jones "hung out together as well as sold drugs

 5   together" (Robbery Trial Transcript at 357), and that Christopher had helped Jones to

 6   lay low in Vermont after Jones said he had committed the robbery (see id. at 365-66).

 7   The government's case also included DNA evidence.

 8         2. The DNA

 9                  On December 21, 2012, as the gun-wielding robber was fleeing, he had

10   discarded not only his gun but also his mask and his hat.    A pursuing NYPD officer

11   spotted the hat, which was tangled up with the mask, and a blue latex glove nearby

12   that visually matched the gloves worn by the robbers seen in the security video. The

13   officer guarded the hat, mask, and glove until an NYPD evidence collection team

14   arrived and took custody of it.    DNA found on the hat ("Hat DNA") matched Jones's

15   DNA profile.

16                  The glove also contained DNA, but from at least three sources.   Both the

17   Hat DNA and that on the glove ("Glove DNA") were analyzed by New York City's

                                                 7
 1   Office of the Chief Medical Examiner ("OCME"). For the Glove DNA, OCME used its

 2   internally-developed, then-usual methodology for this type of mixed DNA sample,

 3   called the Forensic Statistical Tool ("FST").   The government proposed to offer in

 4   evidence FST's analytical conclusion that one of the sources of the Glove DNA was

 5   likely Jones.    Prior to trial, Jones objected to the introduction of FST's Glove DNA

 6   evidence, and the district court ordered a Daubert hearing to determine the reliability

 7   of FST analysis.

 8   B. The Daubert Hearing

 9                   In support of the FST evidence as to the Glove DNA, the Government

10   called two witnesses:   Dr. Craig O'Connor, a Ph.D. in genetics who, at the time of his

11   testimony, was the assistant director at the Department of Forensic Biology at OCME,

12   and had previously served as a criminalist at OCME; and Dr. Adele Mitchell, a Ph.D.

13   in human genetics and molecular biology who had helped develop FST for OCME.

14                   In opposition, Jones called two witnesses, Dr. Eli Shapiro, a Ph.D. in

15   biology who had previously served as a coordinator at OCME, and Nathan Adams,

16   who held a bachelors degree in computer science and was pursuing his masters

17   degree.   Jones also submitted testimony that had been given in another criminal case

                                                 8
 1   by Dr. Ranajit Chakraborty, a population geneticist who had served on a New York

 2   State committee to evaluate DNA analysis methodologies.

 3         1. Testimony of Dr. O'Connor

 4                Dr. O'Connor was recognized, without objection, as an expert in forensic

 5   science and the statistical analysis of DNA evidence.     (See Daubert Hearing Transcript

 6   ("Daubert Tr.") at 10-11.)   His testimony included information on the operations and

 7   accreditation of OCME; the fundamentals of DNA analysis; the design, development,

 8   and validation of FST; and FST's analysis of the Glove DNA.

 9                OCME, founded a century ago, is the largest public forensic laboratory

10   in the country; it is not affiliated with any law enforcement agency. It is accredited in

11   New York by the State's Commission on Forensic Science ("NYS Forensic Science

12   Commission" or "NYS Commission"), and nationally by the American Society of Crime

13   Laboratory Directors Laboratory Accreditation Board.          To maintain its accreditations,

14   and to follow the quality assurance standards and guidelines established by the

15   Scientific Working Group of DNA Analysis Methods ("SWGDAM"), a group run by the

16   Federal Bureau of Investigation ("FBI"), OCME is required to establish and adhere to

17   certain protocols and standard operating procedures for every step of every procedure

                                                  9
 1   an analyst performs in the laboratory.          OCME is regularly audited by the National

 2   Forensic Science Technology Center ("NFSTC"). (See id. at 11-14, 28.)

 3                  OCME began doing DNA testing around 1993.             Dr. O'Connor explained

 4   key terms and concepts of DNA analysis such as "allele," which refers to the

 5   occurrence of a different form of DNA at a specific "locus"--or location--on a DNA

 6   strand.   The alleles at comparable loci vary from person to person and are the basis

 7   of individual DNA profiles.        All DNA analysis begins with several common steps,

 8   including (1) extraction of a DNA sample from a source; (2) "quantitation," i.e.,

 9   estimating the amount of DNA--or "quant"--in the sample, by means of polymerase

10   chain reaction ("PCR"); and (3) amplification, which entails making millions of copies

11   of multiple loci from the DNA sample being analyzed, in order to provide enough

12   material to study.        (See id. at 23-24.)   Dr. O'Connor testified that the estimation of

13   quant had about a 30 percent rate of error--the best that could be expected, even using

14   OCME's quantitation method, which is considered the "gold standard of what's used

15   in the industry" (id. at 24).

16                  DNA samples may be single-source, i.e., contain just one individual's

17   DNA, or may be "mixtures."          A mixture may be simple, in that an individual DNA

                                                     10
 1   profile can be discerned, and thus separated out for analysis, or it may be "complex,"

 2   in that a single DNA profile cannot be discerned and the entire mixture must be

 3   analyzed. (See, e.g., id. at 21.) FST is a program that was developed by OCME in 2008

 4   to analyze complex DNA mixtures.

 5                 FST calculates a "likelihood ratio" (or "LR"), i.e., a statistic reflecting a

 6   "ratio of two different probabilities" that has been commonly used in other scientific

 7   disciplines "for decades." (Id. at 30, 32.) Dr. O'Connor testified that "most laboratories

 8   [were] moving to some sort of likelihood ratio calculation" for analyzing DNA

 9   mixtures, on the recommendation of the International Society of Forensic Genetics.

10   (Id. at 40; see id. at 37-38.)       Likelihood ratios reflect the comparison of (1) the

11   "prosecution hypothesis" that the person of interest contributed to the mixture, using

12   that number as a numerator, against             (2) the "defense hypothesis" that other

13   individuals make up the mixture, using that number as the denominator. (See id. at 30,

14   33.) If the result of dividing the numerator by the denominator is less than 10, it is

15   considered to provide "limited support" for the prosecution's hypothesis; results of

16   10-100 show "moderate support," 100-1,000 show "strong support," and more than

17   1,000 show "very strong support" for the prosecution's hypothesis. (See id. at 33.)

                                                    11
 1                 Dr. O'Connor testified that in the course of validating FST's methodology,

 2   OCME did more than 500,000 comparisons against a database of persons known not

 3   to be DNA contributors, to determine how often the program would generate a false

 4   positive. The results showed that a false positive was generated only .03 percent of the

 5   time. (See id. at 82; see also id. at 151 (testimony of Dr. Mitchell.) Dr. O'Connor stated

 6   that FST had been validated both in-house and by the NYS Forensic S cience

 7   Commission and its DNA subcommittee ("NYS DNA Subcommittee") (see id. at 81; see

 8   also Part I.B.2. below (testimony of Dr. Mitchell)). A summary of FST's validation was

 9   published in a peer-reviewed journal, and FST had been discussed at many

10   presentations and workshops for forensic professionals.

11                 Although OCME was the only laboratory that used FST, Dr. O'Connor

12   testified that FST was generally accepted in the scientific community.        It shared a

13   common approach with likelihood-ratio programs used by other laboratories (with one

14   key difference, see Part I.B.2. below), and these programs generally reach the same

15   conclusion, although the exact figures generated would vary.           An NFSTC audit

16   performed in mid-2012 concluded that FST was not a novel tool. (See id. at 82, 45-46,

17   14-15.)

                                                   12
 1                In 2017, OCME stopped using FST for new cases.            At that time, the

 2   Combined DNA Index System ("CODIS")--the FBI's national database, to which OCME

 3   contributes its data--raised the minimum number of loci that must be amplified

 4   during the preliminary stage of analysis.   FST, which had conformed to CODIS's prior

 5   standards, became incompatible.    Rather than altering the FST codes to comply with

 6   these new standards, and be forced to go through another rigorous validation process,

 7   OCME opted to switch to a DNA testing program that was commercially available.

 8   Dr. O'Connor testified that the change had nothing to do with the validity or reliability

 9   of FST.

10                With respect to the FST analysis of the glove found near the scene of the

11   robbery, Dr. O'Connor testified that OCME had followed its established protocols,

12   including having a supervisor review the initial report to verify that its conclusions

13   were supported by data.       Dr. O'Connor agreed with the report's findings that the

14   sample was a complex mixture of DNA from at least three individuals.          The Glove

15   DNA's likelihood ratio was 1,340, showing very strong support for the prosecution

16   hypothesis that the mixture was composed of DNA from "Jones and two unknown

17   unrelated individuals,"   instead of "three unknown unrelated individuals."           (Id.

18   at 55-56.)

                                                 13
 1           2. Testimony of Dr. Mitchell

 2                  The testimony of Dr. Mitchell, who without objection was qualified as an

 3   expert in human genetics, molecular biology, and forensic science research (see Daubert

 4   Hrg. Tr. 96), included explanations of FST's creation and implementation, its extensive

 5   mock case work in connection with validation, and its manner of dealing with common

 6   phenomena known as drop-out and drop-in.          "Drop-out" describes the situation in

 7   which an allele that is known to exist at a particular locus in the sample is not found

 8   in the analysis; drop-in is the situation in which an allele that is known not to belong

 9   to the person contributing the sample shows up in the analysis.    (See, e.g., id. at 106,

10   109.)

11                  She explained that among DNA testing programs, FST is unique in the

12   way it deals with drop-in and drop-out, as it estimates their likely occurrences based

13   on the amount of DNA in the sample, i.e., the quant.     Although other programs base

14   drop-out estimates on the "height" of allelic peaks that appear during preliminary

15   analysis, OCME tested different methods for a year and found that, on its own

16   equipment, the DNA quant, measured by real-time PCR, was the strongest predictor

17   of drop-out. (See id. at 109-11.) FST's use of quant to estimate drop-out was presented

                                                14
 1   to the NYS DNA Subcommittee, which validated FST's methodology.                  (See, e.g., id.

 2   at 112.)

 3                  OCME also decided to set the ultimate drop-out rate one standard

 4   deviation lower than the quant study suggested, so as to minimize the number of

 5   possible false positives, even though this would also reduce the likelihood ratios

 6   generated for true positives. OCME also limited FST analysis to two- and three-person

 7   samples, because the greater the number of contributors, the higher the drop-out rate.

 8                  OCME's decisions were evaluated and validated both internally and

 9   externally.   According to Dr. Mitchell, validation took a year and a half and involved

10   extensive mock case work--processed according to OCME protocols and replicating

11   common sources of error, such as degradation--on 439 two- and three-person, high-

12   and low-mass mixtures, far exceeding SWGDAM's recommendation of at least 50

13   mixtures.     The NYS DNA Subcommittee approved the FST methods after extensive

14   review throughout the validation process, and its parent NYS Commission granted

15   approval after its own independent review. (See, e.g., id. at 136-39, 159-64.)

16                  OCME's validation also included "noncontributor testing"--i.e., inclusion

17   of 1,200 persons whose DNA was known not to be included in the DNA samples--in

18   order to determine the rate at which FST would produce false positive results by

                                                    15
 1   generating likelihood ratios from the database of noncontributor individuals.          (See id.

 2   at 149.)    Dr. Mitchell testified that of 500,000 likelihood ratios, only 163, or 0.03

 3   percent, were false positives.      (See id. at 151.)     Among the likelihood ratios showing

 4   "very strong" support for the prosecution hypothesis (i.e., a likelihood ratio of over

 5   1,000) there were only 5 false positives, reflecting, in that category, a false-positives

 6   rate of only 0.0009 percent. (See id. at 152.)

 7                  Dr. Mitchell also noted that an alteration had been made to FST's source

 8   code to correct an error discovered after               validation:   Two different statistical

 9   adjustments that were part of the code, if applied to a sample in which the alleles at

10   a given locus added up to 97 percent or more of the allele frequencies in a population

11   (which had not occurred during validation), could yield a likelihood ratio of less than

12   zero, a statistical impossibility, given that both the numerator and denominator in the

13   likelihood ratio must be numbers between one and zero.                OCME considered alleles

14   totaling 97 percent or more to be uninformative because virtually every person could

15   be a DNA contributor to such a site, and to avoid such impossible results OCME

16   simply imposed an allele cap of 97, eliminating from consideration in the ultimate

17   analysis any locus where the alleles totaled 97 percent or more. (See id. at 171-76.) Dr.

                                                      16
 1   Mitchell testified that experts in the field endorse such a method (see id. at 174), and

 2   that this solution generally lowers the likelihood ratio, making it less strong in either

 3   direction (see id. at 177).     She testified that a performance check verified that this

 4   alteration did not interfere with the overall efficacy of the program. (See id. at 177-79.)

 5   The modification was found acceptable in a subsequent audit by NFSTC, referred to

 6   in Dr. O'Connor's testimony. (See id. at 15.)

 7          3. The Defense's Expert Testimony

 8                 Jones's first witness at the Daubert hearing was Dr. Eli Shapiro, who was

 9   allowed to testify as an expert in forensic DNA analysis (see Daubert Tr. 507).         He

10   testified that in his opinion FST does not produce reliable results, because it works in

11   generalizations and does not take into account enough case-specific variables.     (See id.

12   at 509.) He took issue with FST's methods for estimating drop-out, suggesting that the

13   practice of underestimating drop-out leads to inflated likelihood ratios.         (See id.

14   at 586-87.)

15                 Dr. Shapiro had worked at OCME in 2000-2011 as a training coordinator.

16   He had a Ph.D. in biology and had done postdoctoral study in neurobiology; he had not

                                                     17
 1   done any postdoctoral study in statistics, or population genetics, or forensic DNA.     He

 2   acknowledged that he was not a computer expert or a mathematics expert. He was not

 3   a member of any of the professional organizations relating to forensic DNA analysis.

 4   During his time of employment at OCME, he had never used FST. (See id. at 488-90,

 5   502-04.)

 6                  Dr. Shapiro also questioned the legitimacy of OCME's noncontributor

 7   testing.   (See id. at 574.)   He had made a "combined probability of inclusion" ("CPI")

 8   calculation, using data from OCME's validation studies, and had concluded that

 9   OCME's false-positive       studies   underestimated    false-positive rates.   On cross-

10   examination, he acknowledged that CPI does not consider drop-in or drop-out, and

11   thus did not replicate the findings of FST.       He admitted that because CPI does not

12   consider drop-in or drop-out, "LR programs are preferred to CPI in the scientific

13   community." (Id. at 660.)

14                  Jones also called as a witness at the hearing Nathan Adams, who held a

15   bachelors degree in computer science and was pursuing his masters degree.          He had

16   reviewed FST's source code, and he focused principally on the post-validation allele

17   cap modification (described by Dr. Mitchell in Part I.B.2 above).      Adams testified that

18   in his opinion the allele cap rendered FST unreliable, in that it led to different

                                                  18
 1   likelihood ratios.   He opined that more extensive testing was required to determine the

 2   true effect of the modification. (See id. at 684, 752, 755-57.)

 3                  Finally, Jones submitted the trial testimony that had been given in a prior

 4   criminal case in which Dr. Chakraborty, testifying for the defense, opined that FST

 5   was flawed. Dr. Chakraborty had been a member of the NYS DNA Subcommittee that

 6   approved FST. He apparently had seen no flaw in the program to prevent its approval;

 7   his testimony was that his "rationale of voting yes" was "if we don't find any flaw with

 8   it, once it is open to the public, if there is a flaw, it will come out." (Daubert Tr. 847-48

 9   (internal quotation marks omitted).)

10   C. The District Court's Daubert Ruling

11                  Following the close of the five-day Daubert hearing, the district court

12   entered an order denying Jones's motion to exclude FST's Glove DNA analysis; it

13   memorialized the decision in an opinion dated June 5, 2018, see United States v. Jones,

14   2018 WL 2684101 (S.D.N.Y. June 5, 2018) ("Jones I").

15                  The court found persuasive the evidence that had been presented as to the

16   construction and testing of FST, including the procedures OCME used to determine

                                                      19
 1   the validity of its methodology, the manner in which OCME tested for false positive

 2   results, and the empirical process OCME used to develop its drop-in and drop-out

 3   parameters. It noted that OCME's extensive testing of

 4                 over 2,000 DNA samples, drawn from known contributors, of
 5                 varying weights and mixtures, . . . us[ing] that data to deduce
 6                 probabilities of drop in and drop out in a given DNA sample. . . .
 7                 [and] then determin[ing] how often a piece of DNA dropped out,
 8                 . . . revealed that the drop-out frequency correlated with, among
 9                 other factors, the quantity of DNA amplified (i.e., "quant"), the
10                 number of amplification cycles, the number of contributors to the
11                 sample, and the approximate mixture ratio.

12   Id. at *4.

13                 The court also found persuasive the external validation and peer review

14   FST had undergone, first by the NYS Forensic Science Commission and its DNA

15   Subcommittee, describing the latter as "a group of well-known and respected scientists

16   and experts in the field of DNA analysis" whose "members include distinguished

17   experts in the fields of forensic science, population genetics, molecular biology, and

18   laboratory standards," id. at *4, then via audit by the NFSTC, id. at *6, and finally "at

19   numerous conferences and in journals," id.        The court noted that OCME adhered to

20   SWGDAM's guidelines in performing its internal validation. See id. at *5.

21                 The court rejected Jones's contention that FST was unreliable on the basis

                                                  20
 1   that OCME "use[d] quant as a factor in setting the drop-out rates in the FST," rather

 2   than using "peak height." Id. at *5. It noted that OCME made that choice because of its

 3   observation that, when using its own lab equipment, quant, rather than peak height,

 4   was the more predictive as to drop-out.              Given that the use of quant had been

 5   approved by the NYS DNA Subcommittee during its review of FS T, the court found

 6   that "[t]he evidence in the record, on balance, supports [a finding] that OCME's use of

 7   quant rather than peak height is not a flaw, and even if it could be considered a flaw,

 8   it is not large enough to exclude expert testimony on the FST in this case." Id. at *11.

 9                 Having in mind that Daubert sets out five non-exclusive factors that a

10   court may consider in determining the reliability of expert testimony, i.e.,

11                 (1) whether a theory or technique has been or can be tested; (2)
12                 "whether the theory or technique has been subjected to peer review
13                 and publication;" (3) the technique's "known or potential rate of
14                 error;" (4) "the existence and maintenance of standards controlling
15                 the technique's operation," and (5) whether the technique is
16                 generally accepted in the relevant scientific community,

17   Jones I, 2018 WL 2684101, at *7 (quoting Daubert, 509 U.S. at 593-94), the district court

18   concluded that only two of those factors were "in meaningful dispute" in this case:

19   FST's known or potential error rate, and whether FST was generally accepted in the

20   scientific community, Jones I, 2018 WL 2684101, at *9.

                                                     21
 1                  As to the factor of known or potential error rate, the district court held

 2   that while there was no known error rate for FST, OCME's analysis of FS T's false

 3   positives was compelling.         See id.   This component of the validation study "showed the

 4   FST's false positive rate to be very low."              Id.   While there appear to be occasional

 5   typographical numerical or terminology flaws in the opinion--see id. at *5 (referring to

 6   the strong support category, instead of the very strong support category, as showing

 7   the false positive rate of 0.0009%"), and id. at *9 (referring to the very strong support

 8   category as showing the false positive rate of 0.009%")--the court's ultimate conclusion

 9   is perfectly clear.    The evidence at the Daubert hearing was explicit that where the

10   likelihood ratio was "in the very strong support category," i.e., "greater than 1,000," the

11   rate of false positives "was .0009 percent."        (Daubert Tr. 152.) Citing that page of the

12   transcript, see Jones I, 2018 WL 2684101, at *9, and noting that the likelihood ratio

13   calculated for the Glove DNA was 1,340, id., the court concluded that the relevant

14   false-positive rate applicable to the glove was "even lower than the overall false

15   positive rate," of "0.03%," id.

16                  The district court found Dr. Shapiro's critique of OCME's false-positive

17   studies unpersuasive because his "hypothetical study . . . fail[ed] to mimic the

                                                        22
 1   parameters that OCME used in validating the FST, in which OCME considered, among

 2   other factors, both allelic drop in and drop out."    Id.   Instead, Dr. Shapiro had used a

 3   different type of calculation that, "[b]y Dr. Shapiro's own admission," was "disfavored

 4   in the scientific community." Id.

 5                 As to the question of general acceptance, the court found that FST was

 6   generally accepted in the scientific community.      See id. at *10.   It noted that although

 7   OCME was the only laboratory using FST, and Jones's was the first Daubert challenge

 8   to FS T in this Circuit, the court was aware of more than 40 New York State cases that

 9   had rejected challenges to the admission of FST, despite the fact that the New York

10   standards for admission of expert testimony tended to be more stringent than the

11   Federal Rules of Evidence. See Jones I, 2018 WL 2684101, at *8. The district court stated

12   that

13                 nearly every court to have considered the FST has found it to be a
14                 reliable tool that is generally accepted by the scientific community.
15                 Importantly, these court rulings are corroborated by the fact that
16                 the FST has been approved for use in case work by members of the
17                 relevant scientific community and subjected to peer review.

18   Id. at *10.

19                 While Jones argued that FST's unique combination of otherwise accepted

                                                 23
 1   components rendered FST novel and thus not accepted in the scientific community,

 2   the district court noted that Jones had pointed to no evidence from the general

 3   scientific community     (e.g.   a   peer-reviewed article,   a presentation,   or a    study)

 4   challenging the validity of FST.         Although FST's combination of components was

 5   unique, the underlying components themselves were generally accepted, and "'a slight

 6   modification of an otherwise reliable method will not render an expert's opinion per

 7   se inadmissible.'" Id. (quoting Amorgianos v. National R.R. Passenger Corp., 303 F.3d 256,

 8   267 (2d Cir. 2002) ("Amorgianos")).        The court noted that "[e]ach of the assumptions

 9   incorporated into the FST--including allelic drop-out . . . has been the subject of . . .

10   exhaustive testing, validation, peer-review, accreditation, auditing, and other review

11   processes." Jones I, 2018 WL 2684101, at *10.

12                 The court concluded that to the extent that the competing expert

13   testimony could raise a question about the "underlying assumptions" of this generally

14   accepted tool, such debate is best heard by a jury, which may accordingly adjust the

15   weight it gives such evidence.       Id.; see also id. at *11 (even if there are valid concerns

16   about the use of "quant to determine drop-out rates, it is not the role of the courts to

17   weigh the credibility of competing scientific evidence.       Such determinations should be

                                                     24
 1   left to a jury.").

 2                    Similarly, the court concluded that Jones's arguments that FST was less

 3   reliable than traditional DNA evidence, and that FST should not have been used on

 4   this particular sample, were arguments that went to the weight of the evidence, not its

 5   admissibility. Id. at *12.

 6   D. The Trial of the Robbery Charges

 7                    In the ensuing trial on the Robbery Charges, the government presented

 8   some 20 witnesses, who included two witnesses who testified about the Hat DNA and

 9   the Glove DNA, and others who testified to, inter alia, the robbery itself, the capture

10   of one of the robbers, the finding of the hat and glove discarded by the other robber,

11   and the ensuing investigation.        After a seven-day trial, Jones was convicted on all

12   counts.

13                II. THE CHALLENGE TO THE ADMISSION OF THE GLOVE DNA

14                    Jones's only challenge to his convictions on the Robbery Charges is his

15   contention that the district court abused its discretion in admitting in evidence the

                                                   25
 1   Glove DNA. He argues that "FST fails to satisfy Daubert" (Jones brief on appeal at 33),

 2   contending principally that "FST is unreliable because [it] uses predetermined drop-

 3   out rates that do not account for certain real world scenarios" (id. at 26) and because

 4   "so much of what they do is based on estimations," including the allelic frequencies

 5   and the number of contributors to a sample (id. at 28); and he argues that FST cannot

 6   be "generally accepted" because OCME's is the only laboratory that uses it (id.

 7   at 34-35).     He also challenges various aspects of FST's design, including OCME's

 8   decision to use quant over peak height for estimating drop-out rates, and he argues

 9   that FST's overall error rate is 30 percent, the same as the error rate in the

10   determination of quant (see id. at 27-28, 33-34).       He also complains of the decision to

11   use a qualitative, verbal scale for reporting results.            (See id. at 32.)   We are

12   unpersuaded that there was any abuse of discretion in the district court's conclusion

13   that FST evidence was sufficiently reliable to be admitted in evidence and that Jones's

14   contrary contentions go to the weight of that evidence, not to its admissibility.

15                  Federal Rule of Evidence 702 allows the admission of the testimony of an

16   expert witness if

17                  (a) the expert's scientific, technical, or other specialized knowledge
18                  will help the trier of fact to understand the evidence or to

                                                     26
 1                 determine a fact in issue; (b) the testimony is based on sufficient
 2                 facts or data; (c) the testimony is the product of reliable principles
 3                 and methods; and (d) the expert has reliably applied the principles
 4                 and methods to the facts of the case.

 5   Fed. R. Evid. 702.      The fundamental requirements are thus that such evidence be

 6   relevant and reliable. See, e.g., Daubert, 509 U.S. at 587-92; Kumho Tire Co. v. Carmichael,

 7   526 U.S. 137, 141, 152 (1999) ("Kumho").

 8                 "While the proponent of expert testimony has the burden of establishing

 9   by a preponderance of the evidence that the admissibility requirements of Rule 702 are

10   satisfied, . . . the district court is the ultimate gatekeeper." United States v. Williams, 506

11   F.3d 151, 160 (2d Cir. 2007) (internal quotation marks omitted).         In this gatekeeping

12   role, "the district court should consider the indicia of reliability identified in Rule 702."

13   Amorgianos, 303 F.3d at 265. The Supreme Court has observed that many factors "will

14   bear on the inquiry" of whether Rule 702 is satisfied, Daubert, 509 U.S. at 593--

15   including the five non-exclusive factors cited by the district court in Jones I, 2018 WL

16   2684101, at *7--and that "the inquiry envisioned by Rule 702 is . . . a flexible one,"

17   Daubert , 509 U.S. at 594. "[T]he trial judge must have considerable leeway in deciding

18   in a particular case how to go about determining whether particular expert testimony

19   is reliable," Kumho, 526 U.S. at 152.

                                                   27
 1                 Accordingly, both the trial court's decision to admit expert testimony and

 2   the method by which the court reaches that decision are reviewable only for abuse of

 3   discretion. See, e.g., id.; Amorgianos, 303 F.3d at 264. Discretion in this context is broad

 4   and will be found to have been abused only when the decision to admit or exclude

 5   expert scientific testimony was "manifestly erroneous."         E.g., id. at 265 (internal

 6   quotation marks omitted); Boucher v. United States Suzuk i Mot or Corp., 73 F.3d 18, 21 (2d

 7   Cir. 1996) (internal quotation marks omitted).     A decision to admit can be manifestly

 8   erroneous, for example, if the "expert opinion is based on data, a methodology, or

 9   studies that are simply inadequate to support the conclusions reached," Amorgianos,

10   303 F.3d at 266, or if the opinion "is speculative or conjectural, . . . or if it is based on

11   assumptions that are so unrealistic and contradictory as to suggest bad faith or to be

12   in essence an apples and oranges comparison," Boucher, 73 F.3d at 21 (internal

13   quotation marks omitted).     But "other contentions that the assumptions are unfounded

14   go to the weight, not the admissibility, of the testimony." Id. (internal quotation marks

15   omitted).

16                 We see no error, much less any manifest error, in the decision of the

17   district court in the present case.   As detailed in Part I.B. above, the five-day Daubert

                                                  28
 1   hearing exhaustively dissected FST's development, methodology, and implementation.

 2   The court permissibly found that the only two Daubert factors that were meaningfully

 3   in dispute were the known rate of error in FST analysis, and the question of general

 4   acceptance of FST in the scientific community.     It permissibly found that both factors

 5   favored denial of Jones's motion to exclude the Glove DNA evidence.

 6                  While the hearing testimony indicated that FST does not have what

 7   experts would describe as a "known error rate," the court had leeway to find it

 8   appropriate to substitute consideration of the rate at which FST would produce false

 9   positive results.   And in considering the false-positive rate, there was no abuse of

10   discretion in the court's decision to focus on FST's overall rate of false positives

11   instead of, as urged by Jones, limiting its focus to one single early element in the

12   process--the estimation of quant, where there is a 30-percent rate of error.    Notably,

13   all DNA analysis involves quantitation, and the Daubert hearing testimony indicated

14   that the quantitation method OCME uses is considered the "gold standard."        Further,

15   to the extent that FST integrates quantitation more directly into its analysis than other

16   programs do (i.e., in estimating drop-out), the false-positive rate takes this into

17   account.   Thus, despite the rate of error in determining quant, the evidence showed

18   that FST's overall false-positive rate is 0.03 percent, a mere three-hundredths of one

                                                  29
 1   percent; and that for "very        strong support" likelihood ratios (i.e., those more

 2   than 1,000)--including that for the Glove DNA here, which was 1,340--the false-positive

 3   rate is a mere 0.0009 percent.       We see no abuse of discretion in the district court's

 4   conclusion that this evidence indicated reliability sufficient to support admission of

 5   the Glove DNA evidence.

 6                 And, as described in Part I.C. above, the district court clearly explained

 7   its finding that FST is sufficiently accepted--both in its admission in scores of New

 8   York State cases and in "the fact that the FST has been approved for use in casework

 9   by members of the relevant scientific community and subjected to peer review," Jones I,

10   2018 WL 2684101, at *10--to warrant its admission here.

11                 In sum, we see no error, much less any manifest error, in the district

12   court's admission of the Glove DNA evidence in this case.

13                 Finally, we note that even a manifestly erroneous decision will be

14   "harmless," if "it is not likely that [the error] contributed to the verdict." United States

15   v. McGinn, 787 F.3d 116, 127 (2d Cir. 2015).       Were we to consider the district court's

16   decision to admit the Glove DNA in this case to have been error, we would find it

17   beyond any doubt harmless, given all of the government's other evidence that Jones

18   was the gun-wielding robber, including the cell tower data showing that Jones's

                                                  30
 1   cellphone's movement tracked the movement of the robbers, Jones's admission to

 2   Christopher, and the unchallenged evidence that the escaping robber's discarded hat

 3   bore Jones's DNA.

 4           III. CHALLENGES TO THE NARCOTICS CONSPIRACY CONVICTION

 5                Count One of the Indictment alleged that Jones and six other named

 6   defendants, from 2011 through August 2016, conspired to distribute and possess with

 7   intent to distribute five kilograms and more of cocaine, 280 grams and more of cocaine

 8   base, and one kilogram and more of heroin.       Count Two alleged that those seven

 9   defendants carried and used a firearm in furtherance of that conspiracy.    The district

10   court, in addition to ordering that the Robbery Charges be tried separately from the

11   Narcotics Charges, ordered two separate trials for the Narcotics Charges, with Jones

12   scheduled to be tried with just two of the other named codefendants.       As those two

13   codefendants then entered pleas of guilty before the trial, Jones was tried on the

14   Narcotics Charges alone.    As indicated above, he was convicted of conspiracy to

15   distribute and possess with intent to distribute the narcotics; he was acquitted on the

16   count charging him with using and carrying a firearm in furtherance of the narcotics

                                               31
 1   conspiracy.

 2                 In this appeal, Jones contends that he is entitled to a new trial on the

 3   narcotics conspiracy charge, either because the court should have given the jury an

 4   instruction he requested as to multiple conspiracies, or because newly discovered

 5   evidence provided an additional basis for impeachment of Christopher, whom Jones

 6   characterizes as the government's star witness at his trial on the Narcotics Charges.

 7   We find no merit in either contention.

 8   A. Conspiracy Instructions

 9                 Jones complains that the trial court refused to give the jury an instruction

10   he requested with respect to multiple conspiracies, and he speculates that the jury

11   may have convicted him--or may have made findings as to the quantity of narcotics

12   for which he was responsible--on the basis of conduct of members of a conspiracy of

13   which he was not a member. We are unpersuaded.

14                 A defendant complaining that the court declined to give his requested

15   instruction "bears the burden of showing that the requested instruction accurately

16   represented the law in every respect, and that, viewing as a whole the charge actually

17   given, he was prejudiced."     United States v. Applins, 637 F.3d 59, 72 (2d Cir. 2011)

                                                 32
 1   (internal quotation marks omitted).        In order to have a judgment overturned for a

 2   refusal to give a requested multiple-conspiracy charge, a defendant must show both

 3   that there was evidence of "separate networks operating independently of each other"

 4   and that he suffered "substantial prejudice resulting from the failure to give the

 5   requested charge." United States v. Barlin, 686 F.2d 81, 89 (2d Cir. 1982). Where "only

 6   one conspiracy [was] alleged and proved," it is not error for the trial court not to give

 7   a multiple-conspiracies instruction.    United States v. Maldonado-Rivera, 922 F.2d 934,

 8   962 (2d Cir. 1990) (internal quotations omitted).

 9                 We view Jones's requested instruction not only as unnecessary but also

10   as likely confusing.     For example, it stated that "[p]roof of separate or independent

11   narcotics conspiracies is not proof of the single overall narcotics conspiracy charged

12   in the Indictment, unless one of them is the single narcotics conspiracy charged in the

13   Indictment" (Letter from Attorneys for Jones to Judge Broderick dated April 21, 2017,

14   at 1 (emphases added)).        In addition to the fact an "overall" conspiracy would

15   encompass any others--which would not warrant a verdict favoring Jones--this

16   proposed language also raised the conundrum that the conspiracy alleged in the

17   Indictment could be separate from itself.      Jones's request also included an instruction

                                                    33
 1   that the jury could "find that the narcotics conspiracy charged in Count One of the

 2   Indictment did not exist" (id. (emphasis added)), but that some other conspiracy did

 3   exist; and it then discussed the potential for identity of purpose and an "overlap in

 4   membership" of "both conspiracies" (id.)--one of which, by the suggested hypothesis,

 5   did not exist.     We see no abuse of discretion in the court's declining to give Jones's

 6   potentially confusing instructions.

 7                    Jones was the only defendant at his trial. The court duly found a multiple-

 8   conspiracy charge unnecessary "under the facts of this case" and given that "[t]here

 9   is no one else that the jury is considering here" (Narcotics Trial Transcript at 727).

10                    The court properly instructed the jury that in order to convict Jones of

11   conspiracy it must find that he knowingly joined the conspiracy that was alleged in the

12   Indictment.      It also properly instructed that he could not be held responsible with

13   respect to controlled substances dealt with by other persons unless "the type and

14   quantity were either known to [him] or reasonably foreseeable to him, and within the

15   scope of the criminal activity that he jointly undertook."         (Id. at 848.) Jones does not

16   contend that the instructions given were erroneous, and we see no error.

                                                     34
 1   B. Newly Discovered Evidence

 2                After Jones's trial on the Narcotics Charges, the government learned that

 3   Christopher had violated his cooperation agreement by having contraband substances

 4   smuggled into the detention center at which he was being held.       Jones argues that he

 5   could profitably have used that information at trial to impeach Christopher's

 6   credibility and should therefore have a new trial.     The district court denied Jones's

 7   motion for a new trial in an opinion dated July 27, 2018, see United States v. Jones, 2018

 8   WL 3599730 (S.D.N.Y. July 27, 2018) ("Jones II"). We see no basis for overturning its

 9   decision.

10                "A motion for a new trial on the ground of newly discovered evidence is

11   granted 'only in t he most extraordinary circumstances.'" United States v. Parkes, 497 F.3d

12   220, 233 (2d Cir. 2007) ("Parkes") (quoting United States v. Spencer, 4 F.3d 115, 118 (2d

13   Cir. 1993) ("Spencer") (emphasis in Spencer)).   "Newly discovered evidence supports the

14   grant of a new trial only if the defendant demonstrates," inter alia, "that the evidence

15   is 'so material and noncumulative that its admission would probably lead to an

16   acquittal.'" Parkes, 497 F.3d at 233 (quoting United States v. Zagari, 111 F.3d 307, 322

17   (2d Cir. 1997) (other internal quotation marks omitted)).           "'[N]ew impeachment

                                                 35
 1   evidence is not material, and thus a new trial is not required when the suppressed

 2   impeachment evidence merely furnishes an additional basis on which to impeach a

 3   witness whose credibility has already been shown to be questionable.'"               Parkes, 497

 4   F.3d at 233 (quoting United States v. Wong, 78 F.3d 73, 79 (2d Cir.1996) (emphases in

 5   Wong) (other internal quotation marks omitted)).            "[T]he discovery of new evidence

 6   which merely discredits a government witness and does not directly contradict the

 7   government's case ordinarily does not justify the grant of a new trial." Spencer, 4 F.3d

 8   at 119 (internal quotation marks omitted).           We review the district court's denial of a

 9   new trial motion only for abuse of discretion. See, e.g., Parkes, 497 F.3d at 232.

10                  These standards are not met here.        We see no reasonable probability that

11   the new impeachment ammunition against Christopher would have contradicted the

12   government's case.        We note that although Jones refers to Christopher as the

13   government's "star witness" (Jones brief on appeal at 2, 5, 20, 41), Christopher was one

14   of 10 witnesses at the trial on the Narcotics Charges; and there were two additional

15   cooperating witnesses who, like Christopher, testified about Jones's drug trafficking

16   activities.

17                  Further,    we note that Jones had ample opportunity                  to impeach

                                                     36
 1   Christopher's credibility. As the district court stated,

 2                  [Jones] contends that, "[h]ad Christopher admitted these
 3                  additional serious crimes prior to Trial, his credibility would have
 4                  been much more seriously attacked--the result of which would
 5                  have likely been an acquittal." (Def.'s Mem. 5.) As an initial
 6                  matter, in stating that Christopher's "credibility would have been
 7                  much more seriously attacked," (id.), Jones essentially concedes that
 8                  Christopher's post-trial disclosure of the additional crimes
 9                  amounted to cumulative impeachment material. Moreover, the
10                  impeachment material at issue does not          directly contradict the
11                  Government's case, and it is well-settled case law in t his Circuit that
12                  such evidence does not warrant a new trial under Rule 33. See, e.g.,
13                  Spencer, 4 F.3d at 119. Jones had ample evidence with which to
14                  impeach Christopher, including, among other things, (i) his
15                  shooting of four men--likely killing them--when he was
16                  approximately twelve or thirteen years old; (ii) his failure to adhere
17                  to his cooperation agreement by smoking marijuana in jail; and
18                  (iii) his admission that he lied during prior grand jury testimony.
19                  (See Tr. 54-84, 512-16, 532-40, 586-87; GX-13.) Simply put, Jones has
20                  not demonstrated that the new impeachment evidence is "so material and
21                  noncumulative that it s admission would probably lead to an acquittal."
22                  Parkes, 497 F.3d at 233 (internal quotation marks omitted). For
23                  these reasons, I find that the new impeachment evidence is
24                  cumulative, and the discovery of this evidence does not warrant a
25                  new trial.

26   Jones II, 2018 WL 3599730, at *5 (footnote omitted) (emphases ours).

27                  We see no abuse of discretion in this ruling.

                                                      37
1                                        CONCLUSION

2                We have considered all of Jones's arguments on this appeal and have

3   found them to be without merit. The judgment is affirmed.

                                                38