Two bikes have been stolen from outside Foot Locker on Friargate in Preston.
The incident happened at about 3pm on August 9 when a group of four boys spotted four unchained bikes outside the shop. It is thought they stole one bike and then returned to steal a second one.
The bikes were a Mongoose BMX with a green logo, and an orange and white Giant mountain bike with black details on the frame.
PC James Hesketh of Preston Police said: “There were plenty of people in the area when the bikes were stolen and I would appeal to anyone who might have seen this group of boys to get in touch.” Call 101.