Man Who Shot Virginia State Trooper Had 143 Rounds of Unspent Ammo, Police Say

— -- The man who allegedly shot and killed a Virginia State Police trooper at a Richmond Greyhound bus station yesterday had 143 rounds of unspent ammunition, state police superintendent Colonel W. Steven Flaherty said Friday.

James Brown III of Aurora, Illinois –- who allegedly whipped out a handgun and fired at 37-year-old trooper Chad P. Dermyer at point blank range during a routine police training exercise -– had an "extensive criminal history" and a record of gun violence, Flaherty told reporters.

According to police, Brown did not buy the semiautomatic pistol used in the shooting. It was purchased legally 13 months ago, they said, but investigators do not yet know how it ended up in his hands.

"I'm concerned he was able to obtain a gun," said Flaherty. "It is very troubling that he would have a gun."

Immediately following Brown's shots, two other troopers returned fire, wounding Brown, who was later taken to a hospital, where he died of his wounds. Two female bystanders sustained non-life-threatening injuries during the shootout.

Asked if the troopers responded appropriately, Flaherty said investigators are examining the situation, adding, "they were confronted with a hostile situation and they responded to it and eliminated the threat."

Dermyer, a former Marine, succumbed to multiple gunshot wounds sustained in the attack. Survived by his wife and two young children, he is the 62nd Virginia State police trooper killed in the line of duty in the department’s 84-year history, according to the police department.

He was not wearing a bullet-proof vest.

"We encourage our people to wear vests," Flaherty said. But "whether the vest would have saved his life or not, I don't know ... we're talking about a 40-caliber weapon inches from his chest."

ABC News' Jeffrey Cook contributed to this report.