Florida ? A federal agent was fatally shot outside a busy south Florida post office after a fight Tuesday, and dozens of police officers searched the area for the gunman, police said.

The U.S. Customs and Border Protection agent died at Memorial Regional Hospital in suburban Fort Lauderdale less than three hours after the 9 a.m. shooting, police spokesman Sgt. Brian Davis said.

Donald Pettit, 52, was with his young daughter when he was shot, said Carlos Baixauli, a spokesman for the Bureau of Alcohol, Tobacco, Firearms and Explosives.

Pettit was shot once by a man during a possible fight in the post office parking lot, officials said. No one else was injured, and it wasn’t clear whether the shooting was related to the agent’s job. The suspect drove off in a car and police were combing the area for him.

“We’re just going to saturate the area,” Davis said.

A government helicopter hovered overhead and police officers appeared at every major intersection near the shooting scene.