LAWRENCE (CBS) – Three robbery suspects were arrested Friday night after a standoff at a Lawrence convenience store, according to Lawrence police.

The armed masked men wound up locked inside the South Union Market on South Union Street Friday night after the store’s owner hit the alarm and, along with his wife, ran out of the building.

WBZ NewsRadio 1030′s Kim Tunnicliffe reports

A woman who worked at the store was still inside and wound up trapped with the suspects. Police say the suspects pointed a gun at her face and roughed her up. She managed to escape and hide out in a freezer in the back room.

Lawrence police, State Police and Essex County sheriff’s deputies all surrounded the building.

The victim was found shaken up, but uninjured in the store’s freezer.

“This poor woman had to be terrorized,” Lawrence Police Chief John Romero said. “Even when we found her, we had to tell her we were the police and everything was okay.”

Police identified the men they arrested as Michael Alicea, 19, Richard Mora, 18, and Ruben Saldana, 18. Investigators are looking for a fourth suspect who was driving the would-be getaway vehicle.

The three suspects in custody may be tied to six other similar robberies in the area in the last month, according to police.