I had a friend leave a .22 marlin rifle with me about 10 years ago and he has never wanted back. Do I own it?

He has never asked me for it back and now we no longer speak to each other. I don't think he will ever ask me for it back and I was wondering if I could take ownership because I have had it in my possession for so long. Any info would be great. I live in Michigan so I don;t have to re register it.