Can a police officer search a passenger's purse after she has been arrested?

In United States v. Monclavo-Cruz, 662 F.2d 1285 (9th Cir.1981), an officer arrested a female passenger of an automobile and seized her purse, which was either in her hand, on her lap, or on the seat beside her. He did not search the purse immediately, but did so about an hour later in his office, where he had taken both the purse and its owner. We assumed that the initial seizure of the purse was lawful as incident to the owner's arrest, but held that the subsequent search was invalid for lack of a warrant. It made no difference, we said, that the officer was prevented from making the search at the time of the arrest because he believed it would have created a security risk. "The fact that an officer is prevented from conducting a [permissible search at the time of the arrest] is not a sufficient reason to justify a search an hour later at the station. The protection rationale for the search no longer applies." Id. at 1288.