Ryan McMahon stayed on the force after shooting Ronell Foster, a 33-year-old father who police say was riding his bike without a light

Vallejo police have released body-camera footage of an officer chasing an unarmed man in 2018 and fatally shooting him in the back as he was trying to flee.

The police officer, Ryan McMahon, stayed on the force after killing Ronell Foster and went on to shoot Willie McCoy, the 20-year-old who was sleeping in his car at a Taco Bell when a group of officers killed him earlier this year.

The disturbing footage of McMahon shooting Foster, a 33-year-old father who police said was riding his bike without a light, has sparked renewed outrage about the northern California police department and its troubled history of deadly force.

Paula McGowan, Foster’s mother, told the Guardian it was disturbing that McMahon killed her son and remained on the job: “Why is he still on the street? Why is he still on patrol? … It makes me angry as hell. It disgusts me, because it lets me know that they don’t care. They have no rules or protocol.”

On 13 February 2018, McMahon “saw Ronell Foster riding a bicycle at night with no headlamp while weaving in and out of traffic”, Vallejo police said in a statement accompanying the video, released on Monday. The officer then tried to conduct a “traffic stop” for “vehicle code violations”, at which point Foster continued riding his bike away from the officer.

Facebook Twitter Pinterest Body-camera footage of Ryan McMahon chasing Ronell Foster in 2018 and fatally shooting him in the back as he was trying to flee. Photograph: Vallejo police

“I have a guy on a bicycle running from me,” McMahon told a dispatcher. About 50 seconds later, he had killed Foster, announcing “shots fired”.

The body-camera footage is dark and shaky and it is difficult to see what happened. It captured visuals about 30 seconds before the shooting, but not audio. The footage showed Foster struggling on the ground and appearing to try to escape, though it is unclear exactly when the officer fired.

McMahon shot Foster in the back and back of the head, Foster’s attorneys have said in court filings. The footage showed the officer standing above Foster, who is on the ground. McMahon appeared to fire at him from a short distance. When the audio turned on after the shooting, an apparent witness said, “Wow that was bad,” and McMahon said, “I’m OK.”

Vallejo police have continued to allege Foster at one point grabbed the officer’s flashlight and presented it “in a threatening manner”. The grainy footage, however, does not corroborate this assertion and only seems to show the flashlight dropping to the ground.

“The video proves that the official police story is nothing but a fraud,” Adante Pointer, the lawyer for Foster’s family, told the Guardian. “Ronell Foster was unarmed, did not present an immediate threat to anyone and was killed for essentially riding his bike.”

Police have said it was a “violent physical struggle” between the two and that McMahon first tried to use his Taser. But Pointer shared photos with the Guardian that he said showed that McMahon had hit Foster in the head with his flashlight and shot him in the back of the head. He said Foster was also shot multiple times in the back and side.

One of six officers who fired at Willie McCoy had killed unarmed man in 2018 Read more

Vallejo police had repeatedly refused to release the footage, but eventually disclosed it this week following public records requests. Previously, the department had privately shown the video to Foster’s loved ones, who have long insisted that he was killed for no reason even as police publicly pushed the narrative that the officer fired in “self-defense”.

“The story they put out about my son was not true … The public can now really see what happened,” said McGowan, 53. “What I see in that video is him beating my son and murdering him … I want the public to know what these police officers are capable of.”

Facebook Twitter Pinterest Ronell Foster, 33, was killed by Vallejo police in 2018. Photograph: Courtesy of John Burris Law Offices

She said it was clear there were so many ways the officer could have avoided deadly force: “You took his life for a bike.”

Pointer said it was particularly hurtful that the department took so long to release the footage: “It’s heartbreaking, because they have seen their loved one die in a way that is just horrific, but it’s also enraging because the police department has presented the case to the public as if what the officer did was justified.”

‘All these families have to suffer’

McMahon returned to the force and then on 9 February of this year was one of six officers who fired into the car of McCoy, a 20-year-old aspiring rapper who was sleeping in his car. The department has claimed that McCoy reached for a firearm in his lap before the six officers opened fire, but body-camera footage released in March showed they never tried to wake him up and that they fired just after he appeared to scratch his shoulder while still asleep.

McCoy’s death has intensified scrutiny of police in Vallejo, which is 30 miles north-east of San Francisco and has had a flurry of excessive force claims and killings, including numerous cases involving the same officers.

David Harrison, McCoy’s cousin, said on Tuesday that the Foster footage was further evidence that McMahon was a “loose cannon” and that Vallejo police were acting like a “gang” attacking black residents for no reason.

“He’s just allowed to do whatever it is he wants to do, and there’s no culpability,” said Harrison, who has two other cousins who have recently spoken out about Vallejo police using excessive force against them. “These are racist tactics … and all these families have to suffer.”

Marc McCoy, Willie’s older brother, said McMahon’s involvement in both shootings suggested that the officer not only avoided consequences, he also learned nothing about de-escalation and how to avoid using deadly force.

“If your boss is saying it’s OK, you’re going to keep doing it,” McCoy said, adding that he was not confident the footage would make much of a difference: “It feels like no matter what the video shows, you still don’t get an honest answer.”

McGowan said Foster’s children, now ages six and 14, adored their father and now have to deal with the pain of their father’s killing being broadcast on the news.

“Everyone loved my son in Vallejo – he didn’t have one enemy … He had a very good heart,” the mother said, noting that he used to feed homeless neighbors. “I’m devastated. They ruined my whole life. That was my only son.”

McMahon could not be reached for comment and Vallejo police did not respond to inquiries.