Hey. Sorry to hear about the theft. Sometimes people do play pranks on other people. Have you thought about asking them?
I worked with some people, and there was one guy they were always playing pranks on, and one night they took his keys and moved his car (which he loved to death, he slaved to save every penny he made to buy that dream car) into another parking lot. When he got off from work and went out to the lot and did not see his car, he lost it. He went off. He freaked out, he was panicking and all this other stuff. They then told him somebody probably pranked him and he really went off the deep end.
I work very hard for all my money. Everyone does, unless your a dealer or something like that. If I came home and my stuff was stolen, I would not be happy.
Some people handle it nicely. Some people do not. Obviously, it had to have been either his room mates, or one of his room mates friends. I am sure people cannot just walk in and out of their house. If it was not one of the room mates, then it was someone the room mates brought over.
If I was in a situation where I had room mates, and I knew they were bringing their friends, or girl friends over, I would get a drill and a hasp, and put it on my door, and put a lock on my door, and probably even have some way to know if they got into my room while I was gone.
In his situation, if it was me, I probably would do as others have said and gone aggro on some people. Maybe a carbon fiber baseball bat or torches and a mob. Sometimes you have to turn the heat up. Would I go cocked and loaded, no.
At least file a police report, and file against your insurance. You may be able to get some sort of compensation.