I would beat the crap outa him, throw him to the road next to the garbage can with a warning if he ever shows his slimmy face around my place again he gets another whoopin. Then go inside, if cops arive I have not seen this gentle soul in my life and its a crying shame what someone did to his face officer :-) Of coarse Im from Louisiana hahaha we do things a little different, my next suggestion would be to give him a ride to the swamps and let the gators eat him alive!
Now this would be examples of what I would do if he stole my kids bikes from out side, if he stole mine he would be on ice waiting to get puddy filled in his forhead from the 45 cal. hole because I keep my bike inside.