The reason for the plain view doctrine is not exigency of circumstance but rather police convenience. The doctrine dictates that three conditions must be met for seizing without warrant evidence in plain view: prior valid entry, inadvertence, and probable cause. The officer must have entered the premises for some other valid reason and without subterfuge or design to obtain the evidence, which must be inadvertently perceivable in plain view and constitute evidence of an actual crime. The Supreme Court ruling on this issue is ambiguous and plain view has become the law by general usage. The absolute prerequisite for plain view is valid entry, which may be accomplished in the course of making an arrest, pursuing a felon, or receiving through ingratiation the owner's permission to enter. In nonintrusive and preintrusive situations, which are not subject to the fourth amendment at all, the plain view doctrine is inapplicable.