An off-duty Alexandria sheriff’s deputy shot and killed a man who he found had broken into his home in Fort Washington on Tuesday night, authorities said.

The incident occurred just before 11 p.m. in the 8400 block of Rose Marie Drive in Fort Washington, police said.

Lt. William Alexander, a Prince George’s County police spokesman, said the deputy arrived home, saw his front door had been damaged, and then was confronted by a stranger inside. The deputy then shot the stranger, who ran outside and collapsed, Alexander said. He was pronounced dead at the scene.

Investigators believe the deputy interrupted a burglary in progress, and that there was at least one other would-be burglar who fled the scene, police said.

Detectives also were also probing whether others involved might have made off with the deputy’s service weapon, which the deputy could not locate after the incident, law enforcement officials said.

The gun used in the shooting was not the deputy’s his work-assigned gun, Alexander said.

Alexander declined to release the deputy’s name, saying the Alexandria Sheriff’s Office would have to do so, and said detectives were still working to notify family members of the slain man.

The Alexandria Sheriff’s Office declined to identify the deputy, but released a statement saying he had been placed on administrative leave. The sheriff’s department is conducting its own independent investigation into the matter, officials said.

Allison Klein contributed to this report.