Three lockers were forced open and belongings were stolen at a swimming pool.
The thefts took place at Stantonbury Campus at 11.30am on Sunday (7/3).
The swimming pool area was busy around the time of the offence, due to swimming lessons taking place.
Officers are appealing for anyone who witnessed anyone in the area around the time of the offence to contact them as they may have information vital to the investigation.
Call PC Oliver Kitchener on 0845 8 505 505 or Crimestoppers, anonymously, on 0800 555 111.