Can I get a locksmith to pick a lock and then re-lock the door?

Hi - please help me. My housemate has managed to take a load of my stuff including some old trophies my father gave me before he died along with a load of dvds, CDs etc and I just want them back. I have been to the police and they have said that they can't really help because I need proof that they are mine and I don't have receipts etc and it's a domestic dispute! I just want my stuff back - it's really getting me down. I've tried reasoning with him but he wont listen. He has a lock on his door and I was wondering if there was a chance I could get a locksmith in to pick the lock so I can go in and get my stuff who and then lock it back afterward so he didnt notice straight away? Please please please help me - this stuff means a lot to me