PLEASANTON -- The JC Penney store at Stoneridge Mall was burglarized early Thursday by an someone who smashed multiple jewelry cases, police said.

Pleasanton police responded to 1500 Stoneridge Mall Road about 2 a.m. after an alarm went off at the store, Lt. Jim Knox said. Mall security arrived first and found an unsecured door, and security officers and police went in and found two jewelry cases had been smashed.

According to Knox, it does not appear that any cash or other inventory was taken, and that jewelry was the only thing stolen. Store personnel will take inventory of the jewelry Thursday to determine a monetary loss.

According to Knox, it was not immediately clear whether the door was left unlocked or if forced entry had been made. The suspected burglar did not shatter any glass to enter the department store.

No suspects were immediately identified in the burglary, Knox said, though the store has surveillance cameras that were running throughout the night.

Contact Erin Ivie at eivie@bayareanewsgroup.com. Follow her at Twitter.com/erin_ivie.