BOSTON -- A quick-thinking bank employee saved herself and some co-workers early Tuesday after an armed man allegedly tried to hold up a Citizen's Bank branch in Dedham, taking four workers hostage. Bank workers said a well-dressed man who looked like a customer got into the bank using an ATM card and then brandished a gun and demanded money from the vault.

Police said they nabbed the smartly dressed man as he was fleeing the bank on Bryant Street in Dedham after one of four bank workers who was held hostage sent a phone text message to a manager at another branch and he called police.

"Text message from the one of the employees to one of their bank managers, and they called the Dedham police that there was a bank robbery occurring at the Citizen's Bank," Dedham police Lt. Frank Bieliwski said.

That manager alerted officers, and two policemen working a detail at a nearby construction site on Route 1 rushed to the scene in time to arrest the robbery suspect, who was exiting the building.

The arresting officers surrounded the bank and ordered pedestrians to get into the CVS pharmacy next door.

"Officers had their M-16s and their guns drawn and they surrounded the bank and the perimeter," witness Dennis Catalani said.

They said the robbery suspect came out a few minutes later and they almost missed him because he was dressed in a business suit and tie and was driving a stolen BMW.

"The suspect came out of the bank with his hands down and one hand in his pocket. He was ordered to the ground and he refused. He was assisted to the ground and we removed him from the area and placed him in handcuffs across the street," Dedham police officer Frank McMillan said.

They said he had been armed with a handgun, but tossed it in a wastebasket before fleeing the building.

No one was hurt in the incident and police said the robber never got any money because it was so early that the bank had not yet opened its vault.

The detail officers went back to work with a message for the would-be robber.

"He picked the wrong bank today anyway," McMillan said.

The Dorchester man, identified as Delroy George Henry, 34, was taken to the hospital for self-inflicted wounds. It is unclear when he will be arraigned.

Police said there have been several bank robberies in the area in the past few weeks, so they will be investigating to see if there are any connections.