It's a mystery. Was it a bicycle-riding thief on a mission to upgrade his or her ride? Or, was it a heister with a guilty conscience salved by leaving a token replacement for filching a local resident's property?

Ardmore police reports indicate a woman told officers her Smith and Wesson mountain bike was stolen from her residence in the 600 block of 3rd Avenue SW. But the thief apparently left something behind — a bicycle. Why? That's the mystery.

The estimated value of the pilfered bike is $200.

What happened to the bicycle left behind? Police have it in custody.