<human>: Could you distill the essence of the text into 1-3 sentences?

(Sorry if this isn't the right place to post but I don't know where else to ask. If there's another subreddit I should be aware of I'll post this there instead.)

I'm a student, he's a recent grad, and we both live in a house (pretty much a shithole) with four other guys; one of them recently moved in and is subletting from our old roommate, who's gone for 4 months. We've been living here since September; we stay in one room and use a second as a spare bedroom. We've always left our doors unlocked (ughhh :( so stupid I know) and never had any problems with theft before the new guy moved in earlier this month. We've also never met this guy face-to-face because he mostly stayed in his room smoking weed all day. 

We were gone for about a week and a half and when we got back to our apartment today all the things in our spare bedroom were gone - his Wii console and games, sensor bar, Wiimotes and other Wii-related paraphernalia, various Xbox games, my vacuum, even the food and juice in my mini-fridge. The weird thing was the room looked like it was cleaned, too - the garbage that was on the floor was gone and a vase was moved.

We tried to ask all our roommates but only one was home and he didn't see anything. We went to the new guy's room, and knocked on his door. It was locked, but his key was on the floor so we entered his room (desperate measures) and it was completely empty - no clothes, no computer, no sign of anyone living there, but my vacuum cleaner from the other room was in there, so I figure that means he was in our spare bedroom for sure. 

My boyfriend contacted the landlord but no response yet. I've never seen him this upset/pissed off. What I want to know is what can I do to help? Should we report this to police? What kind of thief steals someone's things and then cleans their bedroom? Is it even theft or just someone 'borrowing without permission'? 

Thank you for any help you guys can provide.
<bot>: My boyfriend's Wii and other stuff are gone after a week and a half away; we suspect a roommate might have taken them. WHAT DO? D: