SAN FRANCISCO (CBS SF) — Homicide charges have been filed against former San Francisco police officer Chris Samayoa in the 2017 officer-involved shooting of unarmed carjacking suspect Keita O’Neil, District Attorney Chesa Boudin announced Monday.

Boudin, who promised to crackdown on any police misconduct during his campaign for office, didn’t mince words when announcing the charges against the former rookie officer at a noon news conference.

“In San Francisco there has been a long history of officer-involved shootings leading to no accountability whatsoever,” Boudin said. “Further cementing the idea that police are above the law. That stops today. Earlier this morning my office has filed homicide charges against former San Francisco police department officer Chris Samayoa for his 2017 killing of Keita O’Neil.”

Boudin said it was the first time the San Francisco District Attorney’s Office has ever filed homicide charges against a law enforcement officer.

“After a careful review of all the evidence and the law, this morning we filed the following charges — voluntary manslaughter, involuntary manslaughter, assault by an executive officer, assault with a semi-automatic firearm and neglectful discharge of a firearm,” he said.

The shooting occurred on the morning of Dec. 1. 2017. Samayo, a rookie who was on his fourth day on the job, and his training officer were among those who responded to a report of a robbery and carjacking on the 1800 block of 23rd Street.

A California Lottery white minivan was carjacked outside a corner store at 23rd and Arkansas Street. The woman driving the lottery vehicle was assaulted and suffered non-life threatening injuries.

Another vehicle described as a gold SUV was seen in the area and police believe was involved in the carjacking. The two vehicles were seen traveling together in the Bayview district and police stopped the older model GMC Yukon SUV at the corner of Ingalls and Gilman where four occupants were detained.

The lottery van continued and was chased into a dead-end corner of Fitzgerald Ave. and Griffith St., outside the Alice Griffith housing complex.

Samayoa, who was in the passenger seat of a patrol car that was pursuing O’Neil in the stolen van, had his gun out and was aiming at O’Neil before the patrol car came to a halt, body camera footage released by the Police Department showed.

As O’Neil ran past the officer’s patrol car, Samayoa fired at him from inside the vehicle, shattering the glass. He then fired at an unarmed O’Neil through the car’s window, striking him once.

The bullet struck O’Neil just above the collarbone on the right side. He was transported to San Francisco General Hospital, where he was pronounced dead.

“Mr. O’Neil had no weapons, he was unarmed,” Boudin said. “Body camera footage from other officers shows that not a single other officer pulled out their service weapon or pointed it at Mr. O’Neil. As a result of Officer Samayoa’s terrible, tragic and unlawful decision that day…Mr. O’Neil was killed.”

After a three-month investigation, Samayoa was fired from the department, but there was a public outcry for further action by the district attorney’s office.

The family of O’Neil filed suit against the SFPD for the fatal shooting two weeks after it happened.

April Green, O’Neil’s aunt, expressed gratitude over the charges.

“I am happy to hear this news, and hoping it brings some justice to our family,” said Green.

Supervisor Shamann Walton, whose District includes the area where this crime occurred, said she was hopeful about Boudin’s decision to prosecute.

“Bayview residents deserve to know that law enforcement officers who inflict violence and harm in our community will be held accountable,” Walton said in the press release issued by Boudin’s office. “This prosecution is an important, historic step towards showing that Black lives matter and that unlawful police violence will not be tolerated.”

The San Francisco Police Officer’s Association released a statement regarding the charges against Samayoa.

“Today we were informed of the charges against former police officer Christopher Samayoa. The criminal justice system will allow for the facts surrounding this case to be disclosed,” the statement read. “We are committed to ensuring that Christopher and his family are supported during this difficult time and that he is accorded his due process rights and provided with a vigorous defense against these charges.”

The District Attorney’s Office said it did not request Samayoa’s pretrial detention and a judge signed a warrant for his arrest with a nominal $1,000 bail. Samayoa is expected to surrender on the warrant later this week. It was not immediately clear when Samoyoa would be due in court.