United States v. Daniel Gissantaner, 990 F.3d 457

Police found a pistol in a chest at Daniel Gissantaner’s residence; touch DNA recovered from the gun was a three-person mixture.
Michigan State Police analyst used STRmix (probabilistic genotyping software) to analyze the mixture; STRmix indicated a match between Gissantaner and the minor contributor with a likelihood ratio of 49,000,000:1 (minor contributor ≈7% of mixture, ~49 picograms, ~8–9 cells).
Gissantaner moved to exclude STRmix evidence under Fed. R. Evid. 702 (Daubert), arguing inadequate testing/validation and unreliability for low-level contributors; the district court excluded the evidence after hearings and appointing two Rule 706 experts.
The government appealed interlocutorily; Sixth Circuit reviews legal framing de novo and admissibility for abuse of discretion.
The Sixth Circuit reversed: it held STRmix is generally reliable (testable, peer-reviewed, low error rates, generally accepted) and that the Michigan lab had reliably applied it in this case; lingering disputes go to cross-examination and trial.

Issue	Gissantaner’s Argument	Government’s Argument	Held
Whether STRmix is admissible under Rule 702/Daubert (general reliability)	STRmix is insufficiently tested/validated, controversial, and not generally reliable for forensic use	STRmix is testable, peer-reviewed, has low false-inclusion rates, and is widely used/accepted by labs and the FBI	STRmix meets Daubert factors; generally reliable and admissible
Whether STRmix was reliably applied to this specific sample (low %/low pg contributor)	Michigan lab did not adequately validate STRmix at the very low contribution/quantity here; data presentation incomplete, so application is unreliable	Lab performed internal validation (including low-level tests), followed SWGDAM/FBI guidelines, and the FBI’s validation and peer-reviewed studies support application	Lab reliably applied STRmix here; any remaining concerns are for cross-examination or adversarial testing, not exclusion
Whether the district court properly performed its gatekeeping role and standard of review	Exclusion was appropriate based on perceived shortcomings in testing, peer review, and disagreement among experts	District court misframed Daubert factors and abused its discretion by excluding widely used scientific evidence on this record	Court held the district court misapplied Daubert and abused discretion; vacated exclusion and remanded for trial

Daubert v. Merrell Dow Pharm., 509 U.S. 579 (1993) (sets Rule 702 gatekeeping framework)
Kumho Tire Co. v. Carmichael, 526 U.S. 137 (1999) (trial court’s gatekeeping role and abuse-of-discretion review)
United States v. Bonds, 12 F.3d 540 (6th Cir. 1993) (testing and scientific validity under Daubert)
United States v. Pugh, 405 F.3d 390 (6th Cir. 2005) (legal standard framing review)
United States v. Jones, 965 F.3d 149 (2d Cir. 2020) (admissibility of probabilistic genotyping evidence)
Jackson v. Virginia, 443 U.S. 307 (1979) (government must prove guilt beyond a reasonable doubt)