How to get into someone facebook?

[CCP]

So this guy came over yesterday with a mutual friend. He left first. But today I suddenly got a weird feeling so I asked my mom where my camera was. It's gone. Anyway we all were in the basement and I think I left my camera up stairs but the guy is still shady. I don't think he stole it but I wouldn't put it out him.

But just to make sure I want to see if he's trying to sell it on Facebook or something. The problem is I don't use Facebook much so I don't have him as a friend in there and his Facebook is private. Is there a way I can see his Facebook or somehow hack into it to see if he's trying to sell it or something.

Please help my camera is pretty much all I have and I had to save forever to get it and I would hate for someone to just steal it and get away with it
The legality doesn't concern me I just want my camera back. And most puerile who steal things around here aren't that brite and try to sell it on Facebook