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.
Officer Nicholas O’Malley, a 33-year-old Westfield State graduate and native of Randolph, was arraigned Thursday afternoon in Roxbury District Court on a charge of manslaughter.
A plea of not guilty was entered on his behalf as a courtroom filled with dozens of fellow police officers looked on.
A judge granted O’Malley’s release on his own recognizance with the condition that he surrender any firearms in his possession.
A Boston Police Department narrative detailing the March 11, 2026, incident revealed that there is probable cause to believe 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.
Ian Polumbaum, the assistant district attorney for Suffolk County, detailed the allegations against O’Malley during his arraignment.
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.
“O’Malley’s partner was more in danger from the shots fired than the driver’s vehicle
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.
Suffolk District Attorney Kevin Hayden announced after O’Malley’s arraignment that investigators ultimately determined that his use of force was not justified.
While the body-worn video does exist, Hayden said it will not be publicly released because the investigation into the shooting remains ongoing. He also said the case is heading for a grand jury.
Larry Calderone, president of the Boston Police Patrolmen’s Association, blasted Hayden’s office over O’Malley’s arrest.
“It’s a complete tragedy that we’re here today talking about this,” Calderone said. “We’re here very strongly to tell you that we back our officer...The facts are going to come out. That officer was in fear of his partner.”
Calderone noted that King had several prior run-ins with law enforcement and alleged that O’Malley is being scapegoated.
“None of you know what it is to have your life, your partner’s life, or some other innocent victim, possibly their life in your hands, and have to make that determination in a split second,” Calderone said. “Very easy on Monday morning to take a look at a body camera...I guarantee you have no idea how the officer felt...That body-worn camera doesn’t have human adrenaline.”
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 due back in court in May.
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