The black Charlotte police officer who fatally shot a black man following a brief but tense standoff Sept. 20 won't be charged in the case, District Attorney Andrew Murray announced Wednesday.

Officer Brent Vinson has been on administrative leave since shooting Keith Lamont Scott, 43, in a parking lot while the husband and father waited for his child's school bus.

"It is my opinion that Officer Vinson acted lawfully when he shot Mr. Scott," Murray said. "His use of deadly force was lawful."

The shooting set off fierce protests that resulted in scores of arrests. Police Chief Kerr Putney said after the shooting that Scott was armed and a gun was found at the scene. Scott's wife, who recorded some of the confrontation on her cellphone, said Scott was not armed.

Murray, during a lengthy presentation, showed video of Scott entering a convenience store shortly before the shooting. In the video, a bulge in Scott's lower right pant leg "is consistent with the holster and gun later described by officers and found at the scene," Murray said.

A short time later, Murray said officers were on an unrelated call when they saw Scott parked in his SUV. They ordered him to exit his vehicle after seeing him hold up a semiautomatic handgun, Murray said.

Murray said the videos show that officers told Scott to drop his gun at least 10 times.

"The videos also show that Mr. Scott did not comply with those commands," Murray said. He said Vinson fired four times, hitting Scott three times.

WARNING: Graphic video

Murray said Scott's DNA was found on the gun recovered at the scene.

Murray said he revealed his decision to Scott's family before announcing it publicly. He also discussed his findings with several other prosecutors who agreed with his decision, he added.

Some video from the scene has been released. In September, Putney acknowledged there was "no definitive, visual evidence" that Scott had a gun in his hand. "You see something in the hand and that he pointed it at an officer," Putney said. The department has said officers perceived Scott's movements as posing an imminent threat.

The State Bureau of Investigation took over the investigation, and Mayor Jennifer Roberts said the Department of Justice was monitoring the probe.

Captivating photos of Charlotte protests

WARNING: Graphic video