United States v. Dustin Red Legs, 28 F.4th 931

Defendant Dustin Red Legs lived intermittently with Amy Pritzkau and was observed by Pritzkau entering her ten-year-old daughter L.B.E.’s bedroom near midnight on the night at issue.
Pritzkau later found two sexually explicit photos in a “Photos” folder in Red Legs’s email account that depicted fingers pulling aside underwear to expose a vagina; she identified the victim from blankets, clothing, and a finger blemish.
Metadata from Pritzkau’s screenshots showed the explicit photos were taken about one minute apart at the time Pritzkau saw Red Legs enter the bedroom; metadata linked the explicit photos to a phone matching the make/model of photos stored in Red Legs’s email (including a partial selfie and family photos).
A pediatric examiner testified the victim was a Tanner Stage III female and that the explicit photos depicted a Tanner Stage III vagina.
FBI examiner Anthony Imel compared finger and knuckle creases in the explicit photos to known photos of Red Legs and opined they were from the same person; the district court held a Daubert hearing, admitted Imel’s testimony, and allowed a defense rebuttal expert to testify.
A jury convicted Red Legs of sexual exploitation of a child and possession of child pornography; the district court granted judgment of acquittal on aggravated sexual abuse and sentenced him to 264 months; the Eighth Circuit affirmed, finding any error in admitting Imel’s testimony harmless.

Issue	Government's Argument	Red Legs' Argument	Held
Admissibility of expert identification by finger/knuckle-crease comparison under Rule 702/Daubert	Imel’s FBI training, experience, and comparison methodology were sufficient to assist the jury	Imel lacked qualifications for identity opinions; the field is nascent and he did not rely on the relevant scientific literature or validated methods	District court admitted Imel after a Daubert hearing; the appellate court did not reverse on gatekeeping grounds because any error was harmless
Whether erroneous admission (if any) required reversal	Other overwhelming proof (Pritzkau’s observation, metadata linking photos to Red Legs’ phone/account, victim ID, inculpatory statements, lay-observable similarities) made expert testimony cumulative	Expert testimony was unreliable and could have substantially influenced the verdict	Any error was harmless given the corroborating evidence; conviction affirmed

Daubert v. Merrell Dow Pharms., 509 U.S. 579 (1993) (trial-court gatekeeping standard for expert testimony)
United States v. Omar, 786 F.3d 1104 (8th Cir. 2015) (standard of review for evidentiary rulings)
United States v. Merrell, 842 F.3d 577 (8th Cir. 2016) (test for when improperly admitted expert testimony requires reversal)
United States v. Farish, 535 F.3d 815 (8th Cir. 2008) (harmless-error review for evidentiary rulings)
United States v. Johnson, 860 F.3d 1133 (8th Cir. 2017) (principle that appellate court will not reverse for harmless error)
United States v. Galloway, 917 F.3d 631 (8th Cir. 2019) (benchmarks for reciting facts in light most favorable to jury verdict)