Fargo Police Officer Zack Robinson engaged the gunman who had just shot three of his fellow officers for more than a minute and a half before fatally shooting the man, North Dakota authorities revealed Wednesday in a press conference.

Mohamad Barakat opened fire on Fargo officers during a crash response July 14, killing Officer Jake Wallin and critically wounded Officer Tyler Hawes and Officer Andrew Dotas, officials say.

During a Wednesday press conference state Attorney General Drew Wrigley showed video of Officer Robinson’s response, which was captured by the officer’s body camera.

The video shows Robinson taking cover behind a civilian vehicle, telling dispatch to “send everyone,” and shooting at the gunman.

Wrigley said the driver of the crashed vehicle, Karlee Koswick, tried to run away from the scene and distracted the gunman, drawing his fire and giving Robinson a chance to engage the shooter. Koswick was wounded as she tried to escape.

Robinson’s fire knocked the gunman down and disabled his .223 rifle.

The video shows Robinson advancing on the gunman, ordering him to drop the gun and put his hands up multiple times. The gunman tried to get his rifle back into the fight, failed to do so, and then drew a 9mm pistol.

Robinson fired numerous rounds striking the gunman as he advanced. Then he flanked the gunman by going around the back of the man’s car and shot him multiple times in what appears to be his head. (The video is pixelated.)

Wrigley said Robinson fired 31 rounds in the gunfight and hit the suspect 21 times.

When asked why the officer fired so many round even after the suspect was down. Wrigley sternly reiterated that the gunman was down but still a threat and he was still trying to use his pistol and his rifle after he was initially wounded.

The firefight lasted 1 minute and 46 seconds, according to the attorney general. He said in a real world gunfight, that’s a “lifetime.”

Fargo Police Chief Dave Zibolski said Officer Robinson’s response was an “act of extreme courage and valor.”

Officer Robinson is now returning to patrol.

Officer Hawes and Officer Dotas are recovering from their wounds, as is Koswick.

Barakat was a Syrian national who came to the U.S. on an asylum request in 2012 and is now a U.S. citizen.

Investigation into motives for the attack is ongoing and involves both federal and North Dakota agencies, officials said.