Tenet has gone AWOL

[Jeff Bousquet]

I recently bought a 4 unit. One of the tenets gave notice to the former owner before the closing and has been missing since. He left a bunch  of stuff in the apartment (bed, couch, close, computer), the door unlocked, and the keys on the counter. Do I have to store his stuff or can I throw it out? I haven't been able to get a hold of him.