United States v. Knights Case Brief

Why is the case important?

Respondent was living under specific probationary restraints that permitted a search of his person with or without warrant by law officers. Respondent became a suspect in a vandalism spree. After observation by a detective, respondent was searched and arrested.

Facts of the case

“A California court sentenced Mark James Knights to probation for a drug offense. The probation order included the following condition: that Knights would “”submit his…person, property, place of residence, vehicle, personal effects, to search at anytime, with or without a search warrant, warrant of arrest or reasonable cause by any probation officer or law enforcement officer.”” In the aftermath of arson at the site of a Pacific Gas and Electric (PGE) power transformer, a sheriff’s detective, with reasonable suspicion, searched Knights’s apartment. Based in part on items recovered, including a PGE padlock, a federal grand jury indicted Knights for conspiracy to commit arson, for possession of an unregistered destructive device, and for being a felon in possession of ammunition. In granting Knights’s motion to suppress, the District Court held that, although the detective had reasonable suspicion to believe that Knights was involved with incendiary materials, the search was for “”investigatory”” rather than “”probationary”” purposes. The Court of Appeals affirmed.”


Whether the Fourth Amendment limits searches pursuant to this probation condition to those with a ‘probationary’ purpose.


No. The respondent’s argument, that the probationary purpose limitation follows from our decision in Griffin v. Wisconsin, . . . which was a special needs system, in which, under Wisconsin law, applied to all Wisconsin probationers. In other words, the respondent argued, any search must be a search conducted by a probation officer monitoring whether the probationer is complying with probation restrictions to comply with the Fourth Amendment. The Supreme Court dismissed this, instead focusing on a reasonableness, and that a State’s interest in apprehending violators of the criminal law, thereby protecting potential victims of criminal enterprise, may therefore justifiably focus on probationers in a way that it does not on the ordinary citizen.


The oUnited States Supreme Curt found that the search was reasonable under the general Fourth Amendment approach of examining the totality of the circumstances, with the probation search condition being a salient circumstance. The Court found that defendant’s status as a probationer subject to a search condition diminished his reasonable expectation of privacy. Although the Fourth Amendment ordinarily required probable cause, a lesser degree satisfied the United States Constitution when the balance of governmental and private interests made such a standard reasonable. The court found that when an officer had reasonable suspicion that a probationer subject to a search condition was engaged in criminal activity, there was enough likelihood that criminal conduct was occurring that an intrusion on the probationer’s significantly diminished privacy interests was reasonable. The district court found, and defendant conceded, that the search was supported by reasonable suspicion. Thus, the court held that the warrantless search of defendant, supported by reasonable suspicion and authorized by a condition of probation, was reasonable within the meaning of the Fourth Amendment .

  • Case Brief: 2001
  • Petitioner: United States
  • Respondent: Knights
  • Decided by: Rehnquist Court

Citation: 534 US 112 (2001)
Argued: Nov 6, 2001
Decided: Dec 10, 2001