I had this same problem back in 08 when some dude who I knew 100% stole my shit. I knew for several reasons why it was him.
1. He bragged to me on more than one ocassion about stealling from people in the past
2. I went inside his house and recovered a few minor things from this dued (but not my main possesions that I was after) while his mom was present
3. ANother one of my friends saw him with my [shoes] that he stole
All I can say is the next time you see this dude, look him in his fucking eyeballs and confront him on your stolen shit. Don't have anger in your voice, just let him know that YOU KNOW he stole your stuff. I did this to my clepto and he COULD NOT look me in my eyes and say no he didn't steal my shit. Guilt will eat away at anybody over time, and Karma will eventually do its thing.
If your sure he stole your stuff, Keep the faith bro !