What is the test for seizure of contraband, fruits, or instrumentalities of crime?

It is clear that 'contraband' was not used in its narrowest sense in Skelton, since the items under discussion in that case were various articles of stolen property, which would more conventionally be considered the fruits of crime. On the other hand, the Skelton rule could be construed to exclude evidence that does not fall within any of the traditional classifications: contraband, fruits, or instrumentalities of crime. We do not read Skelton to impose such a limitation. There is no constitutional difference between 'mere evidence' on the one hand, and contraband, fruits, or instrumentalities of crime on the other. (Warden v. Hayden, supra, 387 U.S. 294, 306-307, 87 S.Ct. 1642, 18 L.Ed.2d 782, 792.) We hold that officers may seize any evidence discovered during proper execution of a valid search warrant, subject to the condition of the following paragraph.

The burden is on the police to demonstrate, with regard to any evidence they seize which does not fall within a narrow reading of the warrant's authorization, that they had probable cause for the seizure. 'There must, of course, be a nexus--automatically provided in the case of fruits, instrumentalities or contraband--between the item to be seized and criminal behavior. Thus in the case of 'mere evidence,' probable cause must be examined in terms of cause to believe that the evidence sought will aid in a particular apprehension or conviction. In so doing, consideration of police purposes will be required.' (Warden v. Hayden, supra, 387 U.S. 294, 307, 87 S.Ct. 1642, 1649, 18 L.Ed.2d 782, 792.)

Some of the twelve items seized on December 21 do not meet this test.