Name this horror film please?

i watched this horror film, perhaps a few years back. its about a bunch of friends that have to clean out this abandoned building. and there is a man living there, unknown and he has wires around the house like, under the matresses and stuff so that when someone would sit on the bed, it would ping and he would know where they were in the house. and he was a murderer, and he murdered them, clearly. i thinnnnnk the man who acted as the murderer may of been a wrestler in real life? can anybody put a name to this film? thanks x