United States v. Saemisch, 18 F.4th 50

Saemisch, previously convicted in 1997 of child exploitation (including production and distribution), exchanged coded, graphic emails in 2016 with Dmitry Bron about sex with minors and trading images of child sexual abuse.
Bron, a former prison associate, secretly devised a ruse and later began cooperating with Homeland Security Investigations (HSI); after HSI joined, Bron (with agent approval) communicated with Saemisch via Kik and email.
On May 3, 2016, Saemisch sent five emails containing links and attachments (including cloud-storage links) to images/videos of child sexual abuse to an email address controlled by Bron/HSI; one video matched a file found on a thumb drive in Saemisch’s yard dated February 14, 2016.
At trial Saemisch asserted entrapment and sought to call Dr. Robert Weiss (sex-addiction expert) to testify generally about addiction, triggers, and social isolation to show susceptibility and to distinguish addiction from legal "predisposition."
The district court excluded Dr. Weiss as irrelevant to entrapment (and denied a live proffer), concluding the record showed overwhelming evidence of predisposition; Saemisch was convicted and sentenced to 360 months.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether district court abused discretion by refusing a live testimonial proffer of Dr. Weiss	Government: written expert disclosure sufficed; district court acted within discretion	Saemisch: oral proffer necessary to flesh out expert’s testimony and allow follow-up	No error — written expert disclosure was an adequate offer of proof; refusal to permit live proffer was within the court’s discretion
Whether exclusion of Dr. Weiss’s testimony was erroneous (relevance/admissibility)	Dr. Weiss would explain how addiction and triggers affect susceptibility, showing inducement/predisposition issues	Saemisch: expert testimony relevant to show vulnerability and that addiction is distinct from legal predisposition	No error — testimony was irrelevant because it could not overcome substantial evidence of predisposition and could not opine on legal concept of predisposition or Saemisch’s individual state without examination
Whether entrapment instruction was required	Saemisch argued government/HSI ratified Bron’s prior private inducement and thus inducement plus lack of predisposition supported instruction	Government: evidence showed opportunity not improper inducement; overwhelming evidence of predisposition	Court did not reach ratification question decisively but affirmed exclusion of expert and denial of instruction because Saemisch failed to meet his burden of production on lack of predisposition

United States v. Vasco, 564 F.3d 12 (1st Cir. 2009) (defendant must adduce some evidence to assert entrapment)
United States v. Gamache, 156 F.3d 1 (1st Cir. 1998) (defines inducement and limits of mere opportunity)
Mathews v. United States, 485 U.S. 58 (1988) (predisposition is central to entrapment defense)
United States v. Rodriguez, 858 F.2d 809 (1st Cir. 1988) (two-prong entrapment framework)
United States v. Pérez-Rodríguez, 13 F.4th 1 (1st Cir. 2021) (clarifies modest burden of production and how inducement and predisposition interact)
United States v. Fosher, 590 F.2d 381 (1st Cir. 1979) (trial court may rely on written proffers in ruling on admissibility)
United States v. Powers, 702 F.3d 1 (1st Cir. 2012) (witnesses may not instruct juries on the law)
United States v. Joost, 92 F.3d 7 (1st Cir. 1996) (evidence needed to raise reasonable doubt on entrapment)