The family of a Cameroonian man fatally shot by police on skid row filed a $20-million claim against the city Wednesday, saying officers “initiated” a struggle that ended in a “cop-created killing.”

Charly Leundeu Keunang’s sister, Line Foming, and their parents, Heleine Tchayou and Isaac Keunang, accuse the city of Los Angeles, the Los Angeles Police Department and its officers of excessive force, assault and battery, wrongful death and constitutional violations.

In a letter, lawyers for Keunang’s family called on Los Angeles Dist. Atty. Jackie Lacey to investigate the March 1 death, release police body camera video and criminally charge the three officers who opened fire.

“Law enforcement officers are trained to de-escalate situations and to only use lethal force as a last resort,” the family said in the claim, a legal precursor to a civil suit. “The LAPD officers who killed Mr. Keunang violated these protocols and their reckless mistakes and misconduct resulted in this unnecessary death.”

“I saw everybody standing up while he was on the floor,” Foming said in an interview. ”How can you shoot somebody on the floor?”

Authorities have said Keunang, 43, struggled with one of the officers over his gun during an intense melee. A witness disputed the account.

The claim says six LAPD officers “attacked Mr. Keunang, Tasing him, tackling him to the concrete and repeatedly striking him with their fists and batons. … The officers then shot Mr. Keunang six times from point-blank range as they held him down on the sidewalk.”

Millions of people viewed the confrontation after a witness uploaded a video to Facebook. The shooting brought to light rising tensions between police and homeless people on skid row as downtown Los Angeles’ economic renaissance has left them behind.

Police officials said officers went to talk to Keunang on a robbery call. In surveillance video of the scene, he retreated to his tent, then emerged swinging when they pulled him out.

An officer can be heard making repeated comments about his gun, though his exact words are unclear. Police Chief Charlie Beck told reporters that the officer said, “He has my gun.”

The family’s lawyer, Dan Stormer of Pasadena, said the officer’s gun “never came out of his holster.” The video showed the officer removing his gun from the holster after the shooting.

Foming said she and her parents were suing “so it won’t happen again. Charly, maybe he can rest in peace and know he didn’t die for nothing.”

Keunang, a once-promising math and physics student known on skid row as “Africa,” spent 14 years in federal prison under a stolen French identity for bank robbery, including years in a psychiatric hospital. He hid the conviction from his family and disappeared, relatives said.

Foming said they never stopped searching, and moved to the Boston area in 2006 to press the effort.

“Because of Charly, I put my career on hold,” said Foming’s husband, Charles Foming, who had taught economics at a university in Cameroon.

In June, after his release from prison, Keunang messaged his sister on Facebook. “Your name seems familiar,” he wrote, then added in his native French, “ton jeune frere” (your younger brother).

“Dieu est grand [God is great],” Foming responded.

The family had a three-day reunion in Massachusetts and was in almost constant contact with Keunang after he returned to Los Angeles to obtain travel documents so he could move back to Cameroon and rebuild his life, the claim said.

He also wanted to see his father, who does not have permission to immigrate to the U.S., family members said.

They first saw video of the shooting on television but didn’t know it was Keunang until a relative in Cameroon phoned them, Foming said.

Members of several African immigrant communities are collecting money for a May memorial service and to return Keunang’s body to Cameroon.