Eviction Question: No Contact, Unseen Notice to Quit

[Keith Martel]

So... we purchased a triplex and inherited one tenant on MTM lease in PA. From the time of closing, we've never seen the tenant. Our property manager talked to him once and told him he'd need to get him on a new lease. Since then, the tenants phone number has been disconnected, he's never answered his door, or notes attached to the door.

Finally, we posted a ten-day notice to quit on his door. The notice remained there, untouched, for twelve days. 

Our PM went in and there's a lot of stuff left behind... as if someone is living there. Granted, there's nothing in the fridge.

We've read competing arguments about similar situations. 

Do we go through with an official eviction or bag the dudes stuff and store it in case he comes knocking and get along with turning the apartment over?