Is a defendant required to sign an evidentiary hearing on the issue of probable cause to arrest?

That the district court in the instant case did not abuse its discretion in holding an evidentiary hearing on the issue of probable cause to arrest does not mean that such a hearing was necessary. The court based its decision in part on a perceived Fifth Amendment self-incrimination problem in requiring a defendant to submit an affidavit to demonstrate a factual dispute. The court's Fifth Amendment concerns were unfounded. First, a defendant's attorney can provide the court with the disputed facts through a third-party affidavit, thereby making it unnecessary for the defendant to sign an affidavit. Second, a defendant's testimony in support of a motion to suppress evidence on Fourth Amendment grounds is not admissible against him or her at trial on the issue of guilt unless the defendant fails to register an objection. See Simmons v. United States, 390 U.S. 377, 394, 88 S.Ct. 967, 976, 19 L.Ed.2d 1247 (1968) ("[W]e find it intolerable that [a Fifth Amendment] right should have to be surrendered in order to assert [a Fourth Amendment right].").

The district court also based its decision to hold an evidentiary hearing on the fact that a defendant often does not have complete information regarding his or her arrest at the time a motion to suppress is filed and that, additionally, officers' testimony at a hearing often differs materially from their statements in the police reports. While this lack of information may at times be problematic, it does not warrant a per se rule that an evidentiary hearing must be held on the issue of probable cause to arrest whenever a defendant requests one. Such a rigid rule is not necessary to protect a defendant's Fourth Amendment rights. ⁵ See United States v. Irwin, 612 F.2d 1182, 1187 (9th Cir.1980) (if affidavits show as a matter of law that defendant is or is not entitled to relief, no evidentiary hearing is required).