MEMORANDUM *

Robert Pete Gomez (“Gomez”) appeals his conviction for possession of a firearm in violation of 18 U.S.C. § 922(g)(1). We reverse and remand.

Gomez alleges that the district court committed reversible error when it excused an original juror and impaneled an alternate without: (1) determining whether deliberations had begun; (2) allowing Gomez’s counsel an opportunity to question the juror about her motives for seeking dismissal; (3) questioning the juror about whether she was seeking dismissal because she felt pressure from other jurors to conform to a particular view of the case; (4) determining whether the alternate juror had discussed the case with anyone prior to being impaneled; and (5) instructing the jury to begin deliberations anew once the original juror had been replaced. We agree and reverse Gomez’s conviction.

Under Federal Rule of Criminal Procedure 24(c)(3), a trial court must “ensure that a retained alternate does not discuss the case with anyone until that alternate replaces a juror or is discharged,” and “[i]f an alternate replaces a *705juror after deliberations have begun, the court must instruct the jury to begin its deliberations anew.” Because the court failed to instruct the jury to begin deliberations anew, and because the court did not ensure that the alternate juror had refrained from discussing the case with anyone prior to being impaneled, the court violated both requirements of Rule 24(c)(3).1 Additionally, the court violated Gomez’s Sixth Amendment rights because his counsel was “totally absent” from the hearing in which the original juror was questioned, hence, he was “prevented from assisting the accused during a critical stage of the proceeding.” United States v. Cronic, 466 U.S. 648, 659, 104 S.Ct. 2039, 80 L.Ed.2d 657 (1984).

Although Gomez does not point to specific facts demonstrating that the trial court’s actions prejudiced his case, that is not a responsibility Gomez rightfully bears. It is clear that when a defendant has made a timely objection to an error, as Gomez did here, the government bears the burden of proving that the error was not prejudicial. See Fed.R.Crim.P. 52(a); United States v. Olano, 507 U.S. 725, 734, 113 S.Ct. 1770, 123 L.Ed.2d 508 (1993); United States v. Beard, 161 F.3d 1190, 1194-95 (9th Cir. 1998). The government has failed to meet its burden. Accordingly, we must reverse Gomez’s conviction. Olano, 507 U.S. at 734, 113 S.Ct. 1770.

Gomez also asserts that the district court erred in refusing to give a “mere presence” jury instruction when the government’s case was based primarily on his presence in a car in which the firearm was found. Because we reverse Gomez’s conviction on other grounds, we do not reach this issue. However, should Gomez be retried, the trial court ought to consider Gomez’s theory of the case in determining whether to give a “mere presence” instruction.2

REVERSED AND REMAND.