In United States v. Knights (2001) 534 U.S. 112, the appellant and a friend were suspected of committing arson and vandalizing Pacific Gas & Electric (PG&E) property. A detective saw appellant's friend leaving appellant's apartment around 3:00 a.m. carrying three cylinders that appeared to be pipe bombs. When he looked in the back of the friend's truck, the detective saw PG&E padlocks and various explosive materials. Based on his observations, the officer searched appellant's apartment pursuant to a probation search condition. The Ninth Circuit Court of Appeals found the search was invalid because it was motivated by "'investigatory'" purposes rather than "'probationary'" purposes. The United States Supreme Court rejected this distinction, noting that nothing in the appellant's search condition suggested it was confined to searches bearing upon probationary status. Determining that probation searches need not be justified by probable cause, Knights held "the warrantless search of appellant's apartment, supported by reasonable suspicion and authorized by a condition of probation, was reasonable within the meaning of the Fourth Amendment." Although Knights found the search was supported by reasonable suspicion and, therefore, passed constitutional muster, this does not lead ineluctably to the conclusion that reasonable suspicion is required in all cases. An opinion upholding a particular search does not necessarily hold unconstitutional any search that is not like it.) Because the search in Knights was supported by a reasonable suspicion, the Supreme Court expressly declined to decide whether a probation search by a law enforcement officer without reasonable suspicion satisfies the reasonableness requirement of the Fourth Amendment. In sum, the defendant challenged the warrantless search of his apartment by officers who knew of his probation search condition. The Supreme Court held that, because of a probationer's significantly diminished reasonable expectation of privacy, no more than reasonable suspicion to conduct a search of this probationer's house was needed. (Id. at p. 592.) The court chose to resolve the case on traditional Fourth Amendment grounds, concluding that in the case before them the police had a reasonable suspicion before searching the apartment. (Id. at pp. 591, 593.) The Supreme Court found that the search in question was supported by a reasonable suspicion, it expressly declined to consider "whether the probation condition so diminished, or completely eliminated, Knights's reasonable expectation of privacy (or constituted consent ) that a search by a law enforcement officer without any individualized suspicion would have satisfied the reasonableness requirement of the Fourth Amendment." (United States v. Knights, supra, 534 U.S. at p. 592, fn. 6.)