A security guard at Washington DC’s Census Bureau shot after approaching a car in which two people were arguing has died in hospital.
The gunman, who had kidnapped a woman, barricaded himself inside the bureau before fleeing by car. He was shot in the head by police but survived.
A second officer was shot in the leg during the stand-off about a mile (1.6km) from the US Capitol.
The incident was not related to terrorism, the FBI said.
Police said the security guard, Lawrence Buckner, saw two people fighting in a car that matched the description of a vehicle involved in an armed kidnapping.
When Mr Buckner – whose age was not given – approached the car he was shot in the chest.
The gunman also fired at police cars during a chase before he was blocked in and wounded in a fire fight.
The woman, thought to be the suspect’s wife, got out of the car somewhere between the Census Bureau office in Maryland and central Washington. She was later found alive.
Police said the officer who was shot in the leg is expected to recover.