The court held that the police search of a probationer supported by reasonable suspicion and pursuant to a probation condition satisfied the requirements under the Fourth Amendment.

[1][2] When Mark James Knights was sentenced to summary probation by a California court for a drug offense, the probation order included one condition: 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.” Several days later, Knights and his friend were suspected of committing arson.

Police then searched Knights' apartment without a warrant and discovered items potentially associated with the crime.

"[2] Knights subsequently filed a motion to suppress the evidence obtained from the search.

The District Court granted his motion on the ground that the search was for "investigatory" instead of "probationary" purposes.