FBI agents walk in a line in a snow squall as they look for evidence Thursday in Readington, N.J., near a PNC bank where an FBI agent was killed Thursday in a confrontation with suspected bank robbers. The FBI later said the agent may have been killed accidentally by a colleague.

Readington, N.J. ? An FBI agent who was killed Thursday when a stakeout team opened fire on three armed bank robbery suspects might have been shot accidentally by another agent, the FBI said.

Agent Barry Lee Bush, 52, assigned to the Newark office, died after agents confronted three men suspected in a series of armed bank robberies. Two of the men were captured.

“Preliminarily, information suggests the agent may have been fatally wounded as a result of the accidental discharge of another agent’s weapon during a dynamic arrest situation,” the FBI said in a statement Thursday night.

Pedro Ruiz, an agent in charge of the Newark office, said the suspects did not fire their weapons, which included two assault rifles and a handgun. He said he did not know how many shots were fired and declined to elaborate about what led the agents to shoot.

Bush and his team were tracking a group of men believed to be responsible for four robberies, the FBI said. In two of the robberies, the suspects had fired assault weapons while inside the bank, the agency said.

The agents found three suspects about noon Thursday outside a bank on Route 22 in Readington.

Josh Bavosa, 35, said he was making a business deposit at the PNC Bank when he heard three gunfire bursts that sounded as if they were from an automatic weapon.

When he looked out the window, Bavosa said, he saw law enforcers swarming around a car, pulling two people out and ordering them onto the ground.

Brian Agans, who works in an engine shop across from the bank, said he heard a “pop, pop, pop.” He ran outside to make sure a mechanic wasn’t having a problem with equipment, but instead saw law enforcement.

“All hell was breaking loose. I’ve never seen so many police and authorities take action ever in my life,” Agans said.

Two suspects, Wilfredo Berrios, 28, and Michael Cruz, 21, both of New Brunswick, were captured, officials said. State and local authorities were searching for another man who ran into the woods, identified by state police as Francisco Herrera-Genao, 22, of New Brunswick.

Berrios and Cruz were to be charged with attempted armed robbery of the Readington bank, the U.S. attorney’s office in Newark said.

It was not immediately clear if the men had attorneys, and telephone listings for the men could not be located.

The FBI had started investigating Berrios, Cruz and Herrera-Genao after a March 2 bank robbery, according to a criminal complaint released by the U.S. Attorney’s Office.

After his arrest, Cruz admitted the men were attempting to rob the bank, according to the complaint. He also said they had robbed a bank along with Efrain Lynn, 21, on March 16, authorities said. Lynn was arrested Thursday on a bench warrant unrelated to the bank robberies, federal prosecutors said.

Bush, 52, joined the FBI in August 1987, serving in Kansas City and transferring to Newark in 1991. He is survived by a wife and two grown children, the FBI said.