BOSTON — A Boston police officer who was arrested Thursday on a charge of manslaughter unjustifiably opened fire, killing a man who had allegedly carjacked a woman in the city’s Roxbury neighborhood earlier this month, investigators concluded in court documents obtained by Boston 25 News.
A Boston Police Department narrative detailing the March 11, 2026, incident revealed that there is probable cause to believe Officer Nicholas O’Malley committed voluntary manslaughter by intentionally firing at 39-year-old Stephenson King, causing his death, and doing so without acting in reasonable self‑defense.
Officers responding to 1590 Tremont Street for a reported carjacking on the evening of March 11 spoke with a woman who said she had been seated in the passenger seat of her running vehicle when a male suspect, later identified as King, had assaulted her and dragged her out of the car before fleeing in it.
That information, including the vehicle’s registration, was broadcast to officers citywide.
Two officers later located the stolen vehicle parked at 10 Linwood Square in Roxbury. Body‑worn camera footage captured the officers approaching the vehicle with their firearms drawn and shouting commands at King, who was reclined in the seat, the police report stated.
According to investigators, O’Malley approached the driver’s window while the other positioned himself behind the vehicle. O’Malley then allegedly drew a Taser and yelled, “Bro, I’m gonna f---ing shoot you!”
Authorities say King then shifted the car into reverse and backed toward the officer behind the vehicle, striking a cruiser before moving forward and backward again in an attempt to escape.
Read the full police report:
During the final forward movement, O’Malley fired his gun at least three times, striking King, according to police. King’s vehicle then accelerated, crashed into a stone wall, and came to a stop. Officers removed King and performed CPR until EMS transported him to the hospital, where he was pronounced dead at 10:24 p.m.
An autopsy found that King had been struck three times, with two bullets recovered from his torso. A third projectile was found inside the car’s passenger‑side seat. Investigators say no weapon was found on King or inside the vehicle.
After the shooting, O’Malley allegedly radioed that King had “tried to run us over.” But investigators say body‑worn camera video contradicts that claim, showing that neither officer was in the vehicle’s path when shots were fired.
During an interview, O’Malley allegedly claimed he believed his partner was going to be crushed by the vehicle. However, investigators concluded that the belief was not reasonable based on the video and eyewitness accounts.
The report also cites Massachusetts law stating officers cannot discharge their firearm at or into a fleeing motor vehicle unless necessary to prevent imminent harm to a person, and that such force must be proportionate. Investigators ultimately determined O’Malley’s use of force was not justified.
When asked for a statement on O’Malley’s arrest, Mayor Michelle Wu told Boston 25 News, “I am grateful to District Attorney Hayden and Commissioner Cox for the urgency they have brought to this investigation and for their commitment to transparency in the pursuit of justice. The City of Boston and the Boston Police Department will continue to fully cooperate as this case proceeds.”
O’Malley is expected to be arraigned in Roxbury District Court on Thursday afternoon.
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