United States v. Sergio Herran, 20-10157

Sergio Herran was convicted by a jury for distribution and possession of child pornography and appealed, challenging the denial of his motion to suppress statements made during a police interrogation at his home.
A magistrate judge recommended denying suppression; Herran did not file objections to the R&R, but the district court reviewed the R&R de novo and adopted it in full.
The interrogation occurred at Herran’s residence, involved multiple armed officers who directed and escorted him around his property, confronted him with evidence, and lasted a prolonged period; officers told him near the start that he was free to leave.
Herran alleged his statements should have been suppressed because he was in custody and thus entitled to Miranda warnings; he also argued some trial exhibits should have been excluded under Rules 403 and 404(b).
The Ninth Circuit reviewed the custody question de novo, concluded Herran was in custody for Miranda purposes, reversed the denial of the suppression motion, vacated his conviction, and remanded for a new trial; the court did not reach the evidentiary objections.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether Herran was "in custody" requiring Miranda warnings	Herran: the home interrogation became a police-dominated, custodial atmosphere (multiple armed agents, escorted around property, confronted with evidence, length, pressure)	Gov: not custodial — it occurred at home and officers told him he was free to leave	Court: Custodial; Miranda warnings required — suppression denial reversed
Whether failure to object to magistrate judge R&R waived appellate review	Herran: preserved because he challenges a legal conclusion and district court conducted de novo review	Gov: argued waiver from failure to object to R&R	Court: Legal challenge preserved for de novo review despite no objections
Admissibility of trial exhibits under Rules 403/404(b)	Herran: some exhibits were unfairly prejudicial or improper 404(b) evidence	Gov: exhibits properly admitted	Court: Not decided — issue mooted by suppression reversal

Miranda v. Arizona, 384 U.S. 436 (1966) (establishes Miranda warnings for custodial interrogation)
Thompson v. Keohane, 516 U.S. 99 (1995) (custody determined by whether a reasonable person would feel free to terminate the interview)
United States v. Craighead, 539 F.3d 1073 (9th Cir. 2008) (factors for assessing custody in home interrogations)
United States v. Kim, 292 F.3d 969 (9th Cir. 2002) (custody is mixed question of law and fact; additional factors to assess interrogation pressure)
United States v. Brobst, 558 F.3d 982 (9th Cir. 2009) (confrontation with evidence can contribute to custodial atmosphere)
United States v. Hayden, 260 F.3d 1062 (9th Cir. 2001) (factors assessing detention and pressure)
Miranda v. Anchondo, 684 F.3d 844 (9th Cir. 2012) (failure to object to an R&R affects, but does not automatically waive, appellate review of legal conclusions)
Lisenbee v. Henry, 166 F.3d 997 (9th Cir. 1999) (failure to object to R&R does not automatically waive review of legal conclusions)
Martinez v. Ylst, 951 F.2d 1153 (9th Cir. 1991) (failure to object is a factor in considering waiver on appeal)