It is very sad to hear that, but I have been there myself, so I know, my first bike, a Raleigh Tomahawk got knicked within a few days of me getting it and it turned out to be a jealous pal. My dad saw his dad, I got bike back and I was banned from going near my pal after I exacted revenge on the ex pal for taking my bike.
I wonder when the time will come, maybe it has come, when tracking devices are fitted to cycles.
My father used to tell me, when he was at sea, anyone caught thieving from others had their fingers broken, which is not a bad idea given it is very hard to be light fingered with broken fingers.