Two Dunkin’ Donuts clerks are escorted out of the building Wednesday night after a robbery at the restaurant on Riverside Drive in Auburn.

AUBURN — A quick-thinking clerk thwarted an armed robbery at a doughnut shop Wednesday night, hitting a panic button to let police know a robbery was in progress and telling the man that she had to go in the back to get keys to give him money.

The 22-year-old woman said she was behind the counter at the Dunkin’ Donuts on Riverside Drive around 9 p.m. when a man holding a handgun came in, put a bag on the counter and told her to fill it with money.

The clerk immediately activated an alarm.

“That was it. I pushed the red button,” she said. “I told him, ‘OK, but I need to go out back to get the person who has the keys.'”

The clerk then went into the back room, told her 18-year-old co-worker that the business was being robbed, and locked the door behind her.

Police surrounded the Riverside Drive business soon after she hit the alarm and reported the robbery in progress. For several tense minutes, nobody knew if the gunman was still inside.

The clerks said they could not see the security cameras from the back room and had no way of knowing whether the suspect had left.

“We didn’t know if he had run away or what,” one clerk said.

Auburn police on Thursday released photos of a suspect sought in a Wednesday night armed robbery at the Riverside Drive Dunkin’ Donuts.

With guns drawn, officers made their way to a back door and ushered the clerks to safety. Police continued to search Wednesday night for the suspect, who made off with a tip jar from the counter. He was described as a white man wearing a dark hoodie and possibly blue jeans. The clerks said he was holding a black handgun.

It wasn’t clear Wednesday night if there was a connection between the attempted robbery and a string of 10 holdups in southern Maine since March 20.