WATERLOO — Waterloo Regional Police released photographs of three men they say are connected to a spree of break and enters in university student housing buildings.

The photos and a video show a group of men walking hallways, trying doors to see if they are unlocked.

Police say the rash of break-ins — at least 30 of them — occurred overnight on Aug. 20.

Five student buildings in the area of Hickory Street, King Street North and Spruce Street were targeted.

Some of the goods stolen included electronics such as laptops, phones and video game machines.

All units that were broken into had their doors unlocked.

Police are reminding students to lock their doors and windows and report any suspicious people or vehicles.

Other safety tips include: keeping valuables out of sight, not leaving boxes of expensive items outside the door, using a light timer so the unit looks occupied, keeping a list of the make, model and serial numbers of electronic items and not letting anyone they don't know into a secured building.

Anyone with information on the break-ins can call police at 519-653-7700, ext. 8422, or Crime Stoppers at 1-800-222-8477.