The latest incident happened Tuesday at Lee's Cafe on Mountain Boulevard in the Oakland Hills. But the restaurant owner foiled the robbery attempt because he now locks his door during business hours, only letting in people who look like diners.
Lee, who did not want his whole name used, told ABC7 he saw two men approach his front door around 6 p.m. Tuesday evening. Lee said he walked to the door and was shocked to see the men putting on masks.
The men left after unsuccessfully trying to open the locked door.
Locking doors may be a good deterrent, Oakland Deputy Police Chief Jeffrey Israel said.
"If it makes customers feel safer by being there with the door locked, lock it," he said.
But locked doors are a violation of the state fire code, which requires businesses to keep their doors unlocked when open to the public. When asked for clarification, an Oakland police spokesperson told ABC7 that the department does not encourage business owners to lock their doors.
Over the past two months, their have been 17 armed robberies -- 15 restaurants and two other businesses. Robbers have targeted mostly Asian restaurants on Oakland, but in the past two weeks, there have also been three /*takeover robberies*/ of Chinese restaurants in Castro Valley, Hayward and, most recently, El Cerrito.
Click here for a map of armed robberies around the Bay Area
Oakland police met with concerned merchants in Chinatown to discuss the rash of robberies, which are becoming more violent.
Earlier this week, the Royal Nail Spa in north Oakland was robbed by armed assailants, who pistol whipped an employee.
That same night, a restaurant employee was struck with a gun in another takeover robbery.
Merchants told police the string of robberies is hurting their business.
"Many of them are reporting it's down by 50 percent or more, especially in the evening time," neighborhood crime prevention council member Carl Chan said.
The police need tips to solve the robberies, Israel said. "We really need help from the public and have them come forward and be cooperative with us so we can get the information."
Pharmacist Albert Wong replied that there are not enough bi-lingual officers in the Chinatown substation.
"So when the Chinese-speaking person comes up here now, how are they going to communicate," Wong said. "So they hesitate to come."