LAWRENCE, Mass. (WHDH) -- A clerk at Lightship Liquors was robbed and decided to lock the would-be thief inside the store with her while she waited for police.

The man took a $20 bill off the counter and then tried to leave, only to find he had been trapped inside.

"She was confronted by the individual with a hood on with a knife and took some money and was trying to get out and she locked the door on him," said Anthony Silva, store owner.

The 9-1-1 recording shows the clerk said: “Please hurry. Send somebody.”

The police responded, “Yeah, you shouldn’t have locked him in there with you.”

Police said 19-year-old Dennis Washington came inside the Lawrence liquor store just before 11 p.m. on Monday and he had a knife.

Police said she immediately locked the front door with a button underneath the counter before calling 9-1-1.

Surveillance video shows Washington in a panic to get out. He kicked the front door and came back behind the counter before running to the back door, which wouldn’t open either.

He then ran upstairs trying to get onto the roof, all while holding a knife.

The video shows the clerk yelling at the would-be robber to stop kicking things in the store in an effort to escape.

Police eventually found him downstairs in the basement, hiding behind some liquor, and arrested him. They called the 32-year-old clerk gutsy, but say they don’t recommend doing what she did.

“We don’t want to see anybody injured, and once this individual couldn’t get out, you don’t know how this person is going to respond. And he could have hurt the clerk,” said Police chief John Romero.

Police said that knife is still somewhere inside the store. They think he may have put it down or hid it somewhere while he was running away.