Stolen chain/pedals: What might be the motive? My pedals disappeared. Several months ago, my chain disappeared in the same location. On both occasions, the bike frame was locked, but the totally unsecured quick release wheels and other accessories were undisturbed. There was no evidence of damage. The bike and the components are obviously cheap. What might be the motive for the crime?

The motive is to steal the whole bike.

Since you cannot ride back without pedals or chain, they expect that you will leave the bike locked but unattended at night so they can finish up stealing it without much interference.