A man wearing a ski mask and armed with a handgun entered the store at 333 E. 14th St. around 11:55 p.m.
It turns out the suspect's gun was not loaded, but the employee didn't know that at the time.
"I was a little nervous at first and then it's like adrenaline just kicks in and you don't think about it, you just react," store clerk Mark said.
The suspect confronted the employee at the end of the counter with a gun.
"He demanded money. I had my hands up and he started to swing the gun back and forth. When the gun got close to him, I saw the opportunity and I grabbed it from both ends and I just yanked it out of his hand," Mark said.
The startled man made a run for it and was chased by another employee right out the door. Mark ran right behind them, while he held onto that gun.
The suspect was last seen running on Bellview Drive toward San Leandro Boulevard.
"I thought about my safety, that's why I kept an eye on the gun, but it's like when I saw the opportunity to get it away from him, I took it away from him," Mark said.
Police say it was a brave thing to do, but they don't recommend confronting anyone with a gun.
"This is obviously not something we advocate that the regular person does. It's extremely dangerous, but at the same time in this case it worked out" San Leandro police Lt. Robert McManus said.
Cornell: "Do you feel like a hero?
"No. Heroes are people who rescue others not try to protect themselves," Mark said.
Detectives will review the store's surveillance video to try to identify the suspect and determine whether he may be responsible for similar crimes in the East Bay.
Police said the suspect is described only as being about six feet tall with a thin build.
Anyone with information about this case is asked to call San Leandro police at (510) 577-3230. Those who wish to remain anonymous may call the police tip line at (510) 577-3278.
Bay City News contributed to this story.