Is a prosecutor's closing argument improper reference to the appellants' failure to testify?

Ortiz next argues that the prosecutor's closing argument made improper reference to the appellants' failure to testify. Because the appellant did not object at trial, we review the challenged passages for plain error. United States v. Birges, 723 F.2d 666, 672 (9th Cir.) cert. denied, 466 U.S. 943 (1984). Plain error will only be found where necessary to prevent a miscarriage of justice or to preserve the integrity of the judicial process. United States v. Bustillo, 789 F.2d 1364, 1367 (9th Cir.1986). Having read the relevant portions of the prosecutor's closing argument, we conclude that they do not constitute plain error.

4. Denial of motion to enforce plea agreement.