A JC Penney store at Pleasanton's Stoneridge Mall was burglarized early Thursday morning.
Around 2 a.m. an alarm at the store located at 1500 Stoneridge Mall Road was activated, Pleasanton police Sgt. Kurt Schlehuber said.
Police arrived at the store and saw there had been a break-in and an undisclosed amount of jewelry was taken, Schlehuber said.
Schlehuber said 24-hour mall security personnel responded to the burglary as well.
Schlehuber said investigators are working to track down an unnamed primary suspect, who is believed to have worked alone in the jewelry theft.