Footage taken by bystanders from several angles shows 36-year-old Anthony Lowe abandoning his wheelchair as officers point their weapons at him after allegations he had stabbed someone.
No clear view shows exactly what happened next, but the officers fired around 10 bullets and Lowe, who was Black, died.
The video comes with police action against Black men under the microscope in the wake of the vicious beating of Tyre Nichols in Memphis.
Nichols, 29, died on January 10, three days after he was kicked, punched, pepper-sprayed and hit with batons by a group of officers. Five have since been charged with his murder.
Officers in Huntington Park, a small city within greater Los Angeles, said they responded to reports of an unprovoked stabbing carried out by a man in a wheelchair on Thursday last week.
When they found the alleged suspect holding a 12-inch (30-centimeter) butcher’s knife, the police department said, he ignored commands and threatened to “throw the knife.”
Two attempts to Taser him were unsuccessful.
“The suspect continued to threaten officers with the butcher knife, resulting in an officer-involved shooting,” the police department said.
The videos show Lowe holding a shiny object in his hands, but do not show him going towards officers with it.
Los Angeles County Sheriff’s Department, which routinely investigates such incidents involving officers from the much smaller Huntington Park Police Department, said the man was hit in the torso and pronounced dead at the scene.
Lowe’s family told the Los Angeles Times he had been dealing with mental health issues.
They have not addressed claims he may have attacked someone.
But Lowe’s mother, Dorothy Lowe, told reporters on Monday she wanted action over his death.
“The way they killed my son, they murdered my son in a wheelchair with no legs,” she said.
“So they do need to do something about it, because I do I want justice for my son.”