This just sucks in so many ways I dare not go into them.
For me, solving problems is something like a dog on a bone. I just can't leg go figuring out whatever. When my son was an early teen some jackass stole his moped-- from the school parking lot and he paid for it himself. We were on the case, talking to neighbors, etc. Well, we tracked the sob down and went to court. The SOB had flipped it already and the "judgement" wasn't worth crap cause the idiot had no money. For what it's worth, there was some satisfaction in seeing the guy squirm before he judge.
But really, my point is, you should really try to figure out just who might have done it. Frankly, I don't think it's all that common unless you live in a really tough neighborhood. Point is, there's a connection somewhere between the perp and you. Maybe only a craigslist ad, but the SOB knew you had the bike in the shed, knew when to get it. Not like it was an arbitrary break in of a home.
Good luck and hope you have some good karma on this one. I'd be so pissed!!!!!