FAIRLAWN -- A Pulaski County man was shot and killed Thursday in an altercation with a Pulaski County sheriff's deputy, state police said.

The deputy, who state police did not immediately identify, responded about 5:20 p.m. Thursday to a call at a trailer park on Nice Wonder Way in the Fairlawn section of Pulaski County, said Virginia State Police spokesman Sgt. Michael Conroy.

Upon arriving at the scene, the deputy confronted a man who had allegedly assaulted two people.

When the deputy confronted the man, the man assaulted the deputy with a knife and a blunt object, Conroy said.

The deputy then shot the man twice, killing him, Conroy said.

Conroy said that according to Pulaski County Sheriff Jim Davis, this was the first instance of an officer shooting a suspect in at least 11 years.

The deputy has been on the force for about two years. He was not injured in the altercation, Conroy said.

Residents of the trailer park who arrived there after the incident were not allowed to return to their homes for several hours.

Police have not identified the dead man, but Virginia Martin, 66, of Riner identified him as her brother, 70-year-old John Harvey Collins.

Martin said she talked to Collins on the phone Thursday morning and that he seemed fine. But she said her brother suffered from ongoing mental health problems and had been under the care of a physician for two years.

He often suffered acute symptoms in the spring, Martin said. "Whatever it is that hits him, it hits him in the springtime. And he gets fidgety. He gets real ill."

Martin called the shooting "senseless," pointing out that her brother was small of stature and ill.

"Somebody got him aggravated. And he's already depressed. If he was in his right mind, he never would have hurt anybody," she said.

Martin said she and Collins grew up in Riner, raised by a single mother who depended on welfare to keep the family afloat. Collins served in the Army in the 1950s and later did construction and factory work until he retired.

"He was my only brother. I don't have any other. I don't have no sister. I'm all by myself. I feel like I'm in a nightmare," Martin said.

Residents of the trailer park said Collins sometimes did maintenance work there, and that he had problems with police in the past.

According to Pulaski County Circuit Court records, he was charged in 2006 with felony assault and battery of a police officer and resisting arrest.

The assault and battery charge was not prosecuted, but Collins pleaded guilty to resisting arrest and was sentenced to six months in jail. Five months of the sentence were suspended, the records show.

It could take up to 30 days for state police to complete the investigation of Thursday's shooting, Conroy said.

"We owe it to everybody to do a thorough and complete investigation. That takes time," he said.