BOSTON (CBS) — A lawsuit has been filed against the city of Boston by the family of a man killed in February. Juston Root, 41, was shot at 31 times by police after an incident at Brigham and Women’s Hospital led to a chase.

“At the time Juston was shot in the parking area along Route 9 in Chestnut Hill, he was defenseless, on the ground, semi-comatose, and bleeding profusely. Juston was not brandishing a firearm nor did he have any firearm in his possession,” said a statement from the lawsuit.

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Boston Police Officers David Godwin, Joseph McMenamy, Leroy Fernandes, Brenda Figueroa, and Corey Thomas, and Mass. State Police Trooper Paul Conneely were named in the lawsuit as well.

Root’s family has said Root had a history of mental illness. The lawsuit details Root having disillusions that he was a police officer, sometimes carrying a clear plastic paintball pistol or BB gun.

Juston Root (Family photo)

Police responded to Brigham and Women’s Hospital for a report of a person with a gun back on February 7. According to the lawsuit, two officers shot at Root when he took out an uncharged, unloaded, clear, plastic paintball pistol.

A Brigham and Women’s Hospital valet was hit in the head by Boston Police gunfire. He was left with a serious eye wound.

Root was also shot but he was able to get into his car and drive away. A police chase involving Boston Police cruisers ensued. State Police Trooper Conneely, who was in the area, joined the pursuit.

The approximately six-minute chase ended when Root crashed into another vehicle on Route 9 in Chestnut Hill. According to the lawsuit he then got out of his car, fell, then “stumbled” to the sidewalk severely injured, and in no condition to follow police commands.

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“At the time the 31 shots were precipitously fired, Mr. Root posed no immediate threat, and many alternatives short of the use of lethal force remained,” the lawsuit alleges.

The lawsuit accuses officers of using excessive force, assault and battery, wrongful death, and depriving Root of due process. The city of Boston is accused of negligent training and supervision.

Officers Godin, McMenamy, Thomas, and Fernandes did not have their body cameras on during the shooting, the lawsuit said.

“He was killed without reason,” said Root’s father, Evan Root, at a press conference Tuesday.

Sister Jennifer Root Bannon described her thoughts after hearing police footage. “The overtone was I emptied my magazine on him, congratulations, don’t talk I’ve got my camera going on over here. They would do the tap tap. And I was like whoa, I didn’t know — this doesn’t look like what should be happening here.”

She said she wanted to speak out and to put for better police protocols to put in place.

An investigation by the Norfolk County District Attorney’s Office determined Boston Police and Massachusetts State Police involved in the shooting were justified in their actions.

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Boston Police and Mass. State Police both said they do not comment on pending litigation.