FALL RIVER — The cab driver who fought back against two assailants in his taxi, killing one of them, will not be charged, according to Bristol County District Attorney Thomas Quinn III.

At the arraignment Wednesday of Kyle Dawson, 23, of New Bedford, in Fall River Superior Court, Assistant District Attorney Carolyn Morrissette detailed the events of the attempted armed robbery of the cab driver on August 10 on Bentley Street in New Bedford.

Morrissette said through the investigation, authorities learned that the cab driver had been the victim of an attempted robbery in 2005, and his friend, a fellow cab driver, had been shot and killed during a robbery attempt in 2015.

Following the 2015 murder of his colleague, Donald DePina, the cab driver lawfully obtained a License to Carry a firearm for self-protection.

Morrissette said the cab driver acted in self-defense on August 10 when Dawson and Christopher Dunton, 24, also of New Bedford, placed him in a chokehold in his taxi and held a knife to his side.

"Fortunately he was able to extricate himself and get out of the cab,” District Attorney Thomas M. Quinn III said. “He still faced a potentially life-threatening situation and fired three shots from a handgun he was lawfully entitled to possess and carry."

The gunshots struck Dunton, who was later pronounced dead at St. Luke's Hospital.

Dawson fled the scene but was arrested soon after.

During his arraignment Wednesday, Dawson pleaded not guilty to charges of involuntary manslaughter, armed assault with intent to rob, and two counts of assault and battery with a dangerous weapon. He was ordered held without bail pending a dangerousness hearing on November 8. He had been indicted on the charges earlier this month.

District Attorney Quinn says the charge of involuntary manslaughter filed against Dawson is related to his alleged "wanton and reckless conduct" in the attempt to rob the cab driver. DA Quinn says Dawson's behavior "created a high degree of likelihood that substantial harm would result to another person. The defendant’s intentional participation in this conduct caused the death of Christopher Dunton."