Why won't he give back my stuff?

After dating for 3 1/2 years, my ex and broke up. All was well until about 2 months ago when he went from Dr. Jekyll to Mister Hyde. about a month ago, he decided he wanted to take a break, had them before but we always got back together. This time after a week he decided we were thru. No worries, that's what he wanted, fine by me, hope he is happy. now a month later I call him and ask for my stuff back, soon as I said hello, he hung up on me. after hanging up on me, i had to call a second time. he told me that if I call him again he is going to call the cops on me. I ended up having to call a cop to set up for next Sat. to get my stuff back, and yes there are some high priced things he has, like my washer/dryer he was storing for me, my phone, jewelry etc... My question is why is he so die hard to keep my stuff if he was the one who wanted it to be over, and wants me completely out of his life?