United States v. Jimenez-Bencevi, 788 F.3d 7

Jiménez was charged in a four-count superseding indictment for witness tampering, firearm offenses in furtherance of violence, use of a firearm during and in relation to crimes, and using a cell phone to attempt kidnapping; death-penalty notice was present.
Approximately one month before trial, Jiménez sought a guilty plea in exchange for removal of the death penalty and provided a proffer under direct-use immunity; the government could derivative-use leads but could not use the proffer directly against him at trial.
The district court ordered Stokes, a defense expert, to be informed of the proffer before testifying, effectively allowing use of the proffer to challenge the expert’s testimony and to establish Jiménez as the shooter.
Jiménez was convicted on all counts; the jury recommended life imprisonment rather than death, and the district court imposed life without parole.
On appeal, Jiménez argues (1) immunity agreement violation, (2) improper cross-examination limiting death-penalty exposure inquiry, and (3) insufficient evidence on Count One; the court reverses on the immunity issue but upholds other aspects for potential retrial.
The court concludes the immunity violation was not harmless beyond a reasonable doubt; thus the Count One conviction cannot stand, and Jiménez is remanded for possible retrial on that count.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Did district court violate immunity by using proffer against witness Stokes?	Jiménez	United States	Yes; due process violation; reversal of conviction on Count One
Was cross-examination properly limited regarding death-penalty exposure of cooperators?	Jiménez	United States	No reversible error; Confrontation Clause satisfied
Was there sufficient evidence to convict on Count One after considering the immunity violation?	Jiménez	United States	Evidence sufficient; however, due to reversal on immunity, count may be retried

U.S. v. Melvin, 730 F.3d 29 (1st Cir. 2013) (immunity agreements and due process implications in proffers)
U.S. v. Capozzi, 486 F.3d 711 (1st Cir. 2007) (two-step review of cross-examination limits under Confrontation Clause)
Delaware v. Van Arsdall, 475 U.S. 673 (U.S. 1986) (limits on cross-examination reasonable to avoid harassment and confusion)
U.S. v. Ofray-Campos, 534 F.3d 1 (1st Cir. 2008) (confrontation and bias in witness testimony and cross-examination)
U.S. v. Sepúlveda, 15 F.3d 1161 (1st Cir. 1993) (standard for sufficiency of evidence)
U.S. v. Troy, 583 F.3d 20 (1st Cir. 2009) (sufficiency review and plausible inferences supporting verdict)