United States v. Martin Alcantara-Castillo, 2015 U.S. App. LEXIS 9754

Background

Alcantara was arrested near the U.S.–Mexico border and charged with illegal reentry under 8 U.S.C. § 1326 after Border Patrol Agent Aaron Hunter testified Alcantara spontaneously admitted crossing the day before with a group; Alcantara testified he was in methamphetamine-induced psychosis and did not recall such statements.
Agent Hunter’s alleged spontaneous admissions did not appear in contemporaneous reports or his addendum and were not disclosed until prosecutors prepared for trial months later; Agent Hunter also could not personally identify specific items purportedly found in Alcantara’s backpack.
Defense presented corroboration supporting Alcantara’s account: a psychiatric expert on methamphetamine-induced hallucinations, a photo of a railroad tunnel where Alcantara said he used drugs, and evidence of a gap in the border fence nearby.
On cross-examination the prosecutor repeatedly pressed Alcantara about Agent Hunter’s prior testimony, eliciting Alcantara’s statement that Agent Hunter had “invented” things and then asking directly whether Alcantara’s testimony was that Agent Hunter was inventing stories about him; defense objected and the court overruled.
In rebuttal a senior prosecutor argued the case came down to credibility and improperly vouched for Border Patrol agents by asserting they were “sworn to uphold the law;” the district court sustained an objection and instructed the jury to disregard but denied a requested curative instruction.
The jury convicted Alcantara; on appeal the Ninth Circuit reversed, holding the cross-examination and the rebuttal vouching—taken together—deprived Alcantara of a fair trial and warranted reversal and remand.

Issues

Issue	Alcantara’s Argument	Government’s Argument	Held
Whether prosecutor improperly compelled defendant to comment on a government witness’s veracity on cross-examination	Prosecutor forced Alcantara to impugn Agent Hunter’s credibility (impermissible)	Questions merely confirmed Alcantara heard prior testimony and repeated Alcantara’s own words; not plain error	Yes; forcing defendant to comment on witness truthfulness was improper and plain error
Whether prosecutor impermissibly vouched for government witnesses in rebuttal	Rebuttal invoked extra-record assurances (agents “sworn to uphold the law”) and vouched, undermining fairness	Comment was isolated; district court promptly struck and instructed jury to disregard; harmless	Yes; senior prosecutor vouched by referring to facts not in record—improper and prejudicial
Standard of review applicable to alleged misconduct	Apply plain error (some objections raised, some arguably untimely)	Harmless error when timely objected to; otherwise plain error	Court applied plain error for combined misconduct and reversed because errors affected substantial rights and integrity of proceedings
Whether curative instruction cured prejudice	Minimal curative instruction insufficient given closeness of credibility contest and timing (rebuttal was last argument)	Immediate instruction to disregard cured any harm; no further instruction required	Instruction did not cure prejudice; combined errors materially affected fairness and required reversal

Key Cases Cited

Berger v. United States, 295 U.S. 78 (prosecutor’s duty to seek justice, not just win)
United States v. Combs, 379 F.3d 564 (9th Cir.) (improper to force defendant to call agent a liar; vouching prohibitions)
United States v. Weatherspoon, 410 F.3d 1142 (9th Cir.) (improper vouching and effect of inadequate curative measures)
United States v. Sanchez, 176 F.3d 1214 (9th Cir.) (prosecutor may not assert that agents must be lying if defendant is innocent)
United States v. Ruiz, 710 F.3d 1077 (9th Cir.) (standards for reviewing prosecutorial misconduct and relevance of curative instructions)
United States v. Wilkes, 662 F.3d 524 (9th Cir.) (where case reduces to conflicting stories, inference one side is lying may be reasonable)