It was locked (incorrectly) to a friend's bike that was locked to a stop sign. The seat and wheel were removed to be able to remove it from the lock and other bike and steal it.
Protect your bike – get a security protection label!
Apply the protection label to your bicycle and instantly reduce the risk of theft by up to 50%! Moreover, if the bike is stolen, you increase the chance of its safe recovery by up to 70%.