The mayor of Tacoma, Washington, called for the city manager to fire four police officers after the death of a black man in custody was ruled a homicide.

Manuel Ellis, 33, died on March 3 after being handcuffed and restrained by officers. He could be heard on police scanner traffic saying “I can’t breathe,” after he was handcuffed, and he died at the scene, according to NBC News affiliate KING in Seattle.

A Pierce County Medical Examiner’s Office ruling released this week said Ellis died of respiratory arrest due to hypoxia as a result of physical restraint, KING reported. Contributing factors included methamphetamine intoxication and dilated cardiomyopathy, commonly known as an enlarged heart.

Mayor Victoria Woodards called for the officers’ firing at a news conference streamed on Facebook on Thursday. “Today, it stops in Tacoma,” Woodards said. “We live in a nation where too many black lives have been lost, and I don’t want to see another one,”

Referring to a video that surfaced of the arrest, the mayor said, “As an African American woman, I didn’t need a video to believe,” she said, adding, “It does take a video for so many people to believe the truth about systemic racism and its violent impact on black lives.”

Tacoma is among the many cities across the country that have seen waves of protests sparked by the death of George Floyd in Minneapolis police custody more than a week ago.

The video that appears to show Ellis’ detainment was taken by an anonymous passerby from a vehicle and seems to show two officers punching and then slamming a man to the ground.

The footage was posted on social media by the Tacoma Action Collective and contains profanity and images that viewers might find disturbing. NBC News does not know what occurred before the events in the video.

Police have said that two officers encountered Ellis at 11:22 p.m. as he was walking home and allegedly harassing a woman at an intersection.

When the officers asked what he was doing, police said Ellis claimed he had warrants and wanted to talk to them. Then Ellis repeatedly struck their patrol car, prompting the officers to call for backup before engaging in a struggle to detain him, police said.

“He picked up the officer by his vest and slam-dunked him on the ground,” said Ed Troyer, spokesman for the Pierce County Sheriff’s Department.

There was a struggle before police got Ellis handcuffed on the ground and officers called for paramedics at 11:25 p.m.

Ellis stopped breathing and lost consciousness within a minute of firefighters’ arriving, and he was pronounced dead at the scene. His cause of death was initially listed as pending while medical examiners ran toxicology tests.

The Pierce County Sheriff’s Department is investigating the incident and plans to turn the case over to the county prosecutor next week, KING reported.

The four officers involved were initially placed on administrative leave after Ellis’ death, but were later allowed to continue working. After the medical examiner’s results were released, the officers were again placed on administrative leave, KING reported.

Tacoma Police Chief Don Ramsdell could not immediately be reached Friday morning to comment on the mayor’s call for the officers to be fired.

Ramsdell said in a statement Thursday that the department put the officers on leave while the agency waits for the sheriff’s office to complete the investigation.”We are committed to the investigative process and the integrity of the findings,” the police chief said. “Our hope is that any investigations bring with them answers for everyone involved.”

Tacoma police identified the four officers involved in restraining Ellis as Christopher Burbank, Matthew Collins, Masyih Ford and Timothy Rankine.

In a statement sent to NBC News, union representatives expressed concern that a decision was made on the officers’ fate before the investigation is complete.

”Without any facts, without an investigation, without due process, and with less than a minute of short, blurry, partial Twitter videos in hand, the mayor passed judgment on the actions of four Tacoma Police Officers,” the statement said. “She called them criminals. She called for their prosecution. She called for their termination from employment. And she called for all of these things without an ounce of evidence to support her words beyond misplaced rage.”

Ellis’s family spoke at a news conference flanked by community organizers and civil rights leaders to demand an investigation by the state attorney general.

His mother, Marcia Carter, gave an emotional account of her last conversation with her son: “Those were the last words I heard my son say to me: ‘I love you, Mom. I love you, Mom.’ And I can’t hear that ever again. I won’t be able to hear that.”

Jareen Imam and The Associated Press contributed.