How do I handle this sitch?

So my H's mom, sister and cousin (didn't know about the cousin coming) have been visiting over the last few weeks. Their visits have been staggered and his cousin is the last one to leave today. When she first arrived I came home to see that she was wearing my house slippers. Under a normal sitch this would not be a big deal, but this is on top of all the disrespectful things he has done in the past six months. So I ask where are my slippers. He says he has no idea. What am I am idiot they are on her feet. This was Thursday night.

This is the one that really got me. Apart from my full time job I am also an independent sales consultant for a makeup company.
Saturday I go into the guest bedroom where we have several things stored only to notice in plain view that several of my products are in her suitcase. I don't say anything. Yesterday I ask H, "have you seen my products, several are missing" and I go on to name the items I saw in her suitcase. She pretends to be ignoring the conversation, but I see her turn to him when she thinks I am out of the room and ask him about it. They say something in Greek I don't understand. This morning I notice that she has taken the care to hide the products under the lining of her suitcase. I go to H and say, "why are my products in there" and I point to the bedroom. He walks over to the bedroom and I leave because 1. No matter what his friends and family say or do I am the bad guy 2. We are going to the intensive on Friday and I don't want to make waves 3. I don't know who took it, but I do know that whether she knew or not at the time that it was wrong she knows now and has not only not come clean, but tried to hide the fact that she has them.

How do I respond to this. Either my H, SIL, or his cousing took the products and stole from my biz. This is BS. She is leaving today so I can't confront her and she will probably deny it if I bring it up to H. Or H will deny it if he took them. Point is I don't think that anyone will come clean particularly him if he took it, but stealing from my biz is NOT OK. I don't think I can or should let it slide. Am I wrong?


Posts
Role Reversal(original)
WAW now LBS part I & II
WAW now LBS part III(current)
T: 9 yrs
M: 8 yrs
WAW: Sep 06-Jul 07
LBS: Sep 07-pres.