The Basics of Suppression Hearings

When a defendant seeks to exclude evidence allegedly obtained in violation of the constitution, the judge normally decides the suppression motion by preponderance of the evidence.83 With most court motions, the burden of persuasion is on the moving party, meaning that a tie is resolved in favor of the non-moving party. Accordingly, a defendant arguing that a magistrate issued a search warrant without probable cause would have the burden of proof. There are, however, situations in which the prosecution bears the burden of proof. When a confession is challenged as involuntary, for example, “the prosecution must prove at least by a preponderance of the evidence that the confession was voluntary.”84 

When defendants seek exclusion of evidence on constitutional grounds, the standard procedure is for the judge to hold a “suppression hearing” outside the presence of the jury. Each side may present witnesses. Police officers commonly testify about what things they observed in advance of a Terry stop or arrest that justified a seizure under review. They also explain what evidence provided probable cause to justify warrantless searches under doctrines such as the automobile exception and exigent circumstances. Defendants may testify in support of their suppression motions, and absent unusual circumstances, their testimony at suppression hearings may not be used against them at trial.85  Under this rule, a defendant may testify that a suitcase belonged to him in order to establish standing to object to an unlawful search of the suitcase, without providing the prosecution a damaging admission usable to prove guilt. If the judge finds for the defendant, then the excluded evidence cannot be shown to the jury. In cases where the prosecution’s primary evidence is challenged as unlawfully obtained—for example, a gun seized from a defendant who is then charged with unlawfully possessing it—a suppression ruling in the defendant’s favor can result in the dismissal of the charges. A defendant who loses her pre-trial suppression motion may, if subsequently convicted, raise her suppression arguments again on appeal.

Our next case explains how courts resolve allegations that a search warrant was issued on the basis of false statements made by police officers to the issuing magistrate.

Notes, Comments, and Questions 

The details of suppression motion practice differ markedly among jurisdictions and even among judges in the same courthouse. Students who eventually practice criminal law must study carefully the rules and preferences of the judges before whom they appear. The overwhelming bulk of criminal cases never go to trial, and suppression hearings are often the most important court proceeding in a case.

One risk of which defense counsel must be aware concerns the use of suppression hearing testimony against a defendant should a case eventually go to trial. While such testimony cannot be used during the prosecution’s case in chief (that is, cannot be used substantively to prove the defendant’s guilt), see Simmons v. United States, 390 U.S. 377, 390 (1968), it can be used to impeach the defendant should her trial testimony contradict what she said at the hearing. See, e.g., United States v. Beltran-Gutierrez, 19 F.3d 1287, 1290–91 (9th Cir. 1994); United States v. Geraldo, 271 F.3d 1112, 1116 (D.C. Cir. 2001).