Four restaurants, two in La Habra and two in Whittier, were broken into early Thursday morning, apparently by the same thief, police said.
All four crimes took place along Whittier Boulevard between 1 and 2 a.m., according to authorities. No injuries were reported.
A rock was used in all of the break-ins to smash windows, some of which were boarded up early Thursday.
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The first restaurant that was hit was California Sushi & Teriyaki in La Habra, but nothing was stolen. The next restaurant targeted was My Pizza Pub, where the thief took cash and two small safes.
Authorities are checking surveillance video from the restaurants that show one man wearing shorts inside the restaurant.
The next two restaurants were in Whittier. Rosarito Taco Grill was broken into just before 2 a.m., but it appears nothing was taken from the business.
The last restaurant, Casa Olvera, was burglarized about five minutes later, according to police. Cash was taken from a register.