Inova Fairfax Hospital Center is seen in this file photo. (Cliff Owen/AP)

Sheriff’s deputies normally guard the jail in Fairfax County, but when a call crackled over the radio Monday night about a man wielding a weapon at an INOVA Fairfax Hospital bus stop, a veteran deputy nearby hurried to the scene, police said.

The 29-year-old man had struck a security guard with a metal sign post and appeared to be in the throes of a mental health episode, so the deputy tried to calm him, police said.

But police said the man raised the sign post over his head and charged the deputy, who ordered him to drop it and backed up. The man did not comply, and the deputy fired on him multiple times, police said. He later died at the hospital.

Detailing the incident at a news conference Tuesday, Fairfax County police and sheriff’s office officials said that the 18-year deputy had the authority to respond to the call, that he had received training on handling people with mental illness and that he tried to de-escalate the situation.

Fairfax County Police released this image of a metal sign post that authorities say was used to threaten a deputy at Inova Fairfax Hospital. (Fairfax County Police)

“I think it was absolutely appropriate,” Fairfax County Police Chief Edwin C. Roessler Jr. said of the deputy’s decision to respond to the call.

Roessler said the police were still working to confirm the identity of the dead man, who was described as Hispanic.

Authorities declined to identify the deputy who was involved in the shooting. They said he had been placed on routine administrative leave pending the completion of the police investigation and an internal review by the sheriff’s office.

Roessler said the incident began after security guards at the hospital escorted the man, who was a patient, to a bus stop on Wellness Boulevard near the hospital’s Green Garage. INOVA Fairfax Hospital officials said medical privacy laws prevented them from discussing the man’s treatment.

Shortly before 10 p.m., hospital security got a call that the man was wielding a weapon at the bus stop, Roessler said. Guards responded and the man struck a guard with the sign post, which had a spade-like bottom for insertion into the ground, Roessler said.

A radio call went out on the hospital security channel, and calls were placed to 911. Fairfax County Sheriff Stacey A. Kincaid said the deputy heard the call because he was at the hospital guarding a patient from the jail. The deputy responded and was the first law enforcement officer on the scene.

“My deputies have both criminal and civil jurisdiction in Fairfax County,” Kincaid said. “They can respond to any incident where the public safety is at risk.”

The Fairfax County Police Department generally provides policing in the county, while the sheriff’s office guards the jail and courthouse and serves civil documents.

Fairfax County police officials said the encounter between the deputy and the man was over in a matter of minutes. Roessler said surveillance cameras at the hospital captured the action, but he said he would not release the video until authorities make a decision on whether to press charges in the case.

The county sheriff’s office had previously been criticized by mental-health advocates for its handling of Natasha McKennan, a schizophrenic inmate who died following an encounter with deputies at the jail in 2015. Prosecutors decided not to press charges in the McKennan’s death.

Pete Earley, a mental-health advocate in Virginia and former Washington Post reporter, said the question that most concerns him is not why the man was shot but why he was released from the hospital.

“We need to back up and ask what happened inside the hospital,” Earley wrote in an email. “If he were psychotic, why was he released? The fact that security was needed to escort him to a bus stop suggests that he was unstable and possibly violent.”