STROUDSBURG, Pa. (AP) — Pennsylvania State Police troopers were justified when they shot and killed a distraught 19-year-old man who had brandished a pellet gun at them on an overpass in the Pocono Mountains, a district attorney said Tuesday as authorities released video of the fatal encounter.

Troopers went to the Route 33 overpass over Interstate 80 on Dec. 30 in response to a report of a suicidal man and found Christian Joseph Hall standing on the ledge, authorities said.

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Troopers spent about 90 minutes trying to persuade Hall to give up and drop the weapon, saying “we are here to help you” and offering him food, drink and a blanket. But he approached them while brandishing the pellet gun, and they opened fire, said Michael Mancuso, first assistant district attorney in Monroe County.

“Frankly I’m astounded that they let him get so close with the threat he was presenting. It was clearly the last thing they wanted to do, was to open fire on him,” Mancuso said. “It was a classic ‘suicide by cop’ scenario.”

Hall himself had called 911 anonymously to report a possibly suicidal man on the bridge, Mancuso said.

Hall’s family has criticized police for the fatal shooting, saying he was in the throes of a mental health crisis. The local chapter of the NAACP has called Hall’s death avoidable. The shooting prompted a march in Stroudsburg earlier this month.

“He needed help. He was looking for help but instead of getting help he was killed by those who were supposed to help him,” Fe Hall, his mother, said at a recent news conference.

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Civil rights attorney Ben Crump represents Hall’s family and has said a lawsuit is in the works. Crump planned to release a statement on the DA’s findings, his office said Tuesday. Hall was Chinese American, according to Crump’s website, and was adopted by multiethnic parents.

The district attorney’s office played a previously unreleased dash cam video of the shooting that showed troopers assuring him he wasn’t in any trouble and offering assistance.

“I’m not sure what’s going on in your head, but this is not the end of the world. Just a little bump in the road,” a trooper said at one point, video showed.

Eventually, Hall took several halting steps toward the troopers as they repeatedly yelled at him to “put it down.” Hall appeared to be holding the gun at his side when they fired several shots at him and missed, according to the video. He then raised his arms in the air, took another step and was waving the gun when they fired again and hit him, the video showed.

The moment of the shooting itself was blurred out in the footage released. Mancuso said Hall was about 70 feet (21 meters) away from the troopers when he was struck. He was pronounced dead at a hospital.

The gun that Hall was holding turned out to be a pellet gun that resembled a Walther semi-automatic pistol, Mancuso said.

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