It can be a crime if you stole his ID. Pursuant to RCW 9A.56.330. (1) A person is guilty of possession of another's identification if the person knowingly possesses personal identification bearing another person's identity, when the person possessing the personal identification does not have the other person's permission to possess it.
It can also be a crime pursuant to RCW 9.35.020, as Identity Theft. Under this law no person may knowingly obtain, possess, use, or transfer a means of identification or financial information of another person, living or dead, with the intent to commit, or to aid or abet, any crime.
