Can a known thief convince you that they didn't do it?

Three things tend to go together a liar a cheat and a thief. Ask any convict in prison 90% will swear they are innocent. Crying showing emotional distress etc. is all part of the lie. I am not saying she did the deed but I am saying that if she stole before then there is a reason she is suspect. My suggestion is that next time you have a party leave her name off of the invite list. Or better yet set up a room with a camera (nanny cam) in it. A picture is worth a thousand words (and tears) I would not be surprised if there was more than one thief there and it would be nice to know who is who. any how short of a lie detector (and even then) I don't know how to get the truth out of a thief hope that I was some help...R