Thunder Bay police are warning business owners to review their security systems after a rash of break-ins on the city's south side.

In a release issued Wednesday, police said they've received more than 30 reports of early morning break-ins since the beginning of January.

In most of the incidents, the thief used a brick or pole to smash through the glass on the front entrance of the building, police said.

"Cash has been the primary target of these break-ins," the release stated, "however some electronic devices have been reported stolen."

Police said a "person of interest has been observed" in the area of some of the incidents.

The man has a medium build and wore a tan work jacket or light-coloured hoodie, Police said they believed the man was travelling on foot and would be carrying a backpack, messenger bag or shopping bag of some sort to carry tools and stolen goods.

Police ask anyone with information on these break-ins to call Thunder Bay police at 684-1200 or Crime Stoppers at 1-800-222-8477.