Police in the United States have been criticised after shooting dead a black man in a wheelchair.

Officials at Delaware's Department of Justice are investigating the shooting of Jeremy McDole, 28, by officers who were responding to a 911 call saying he had shot himself.

Footage posted online showed officers repeatedly urging Mr McDole, who onlookers said was bleeding, to raise his arms.

After around a minute of failing to do so, he appeared to reach into his pocket, at which point officers opened fire multiple times.

Wilmington's chief of police later said they had found a .38-caliber handgun by his side, though the family disputed this. No gun was visible in the footage.

Warning: Some viewers may find this footage distressing

Speaking to the press, Mr McDole's mother Phyllis said: "This was murder... He shot my son like roadkill."

They shot my son so much he fell out of his wheelchair... He fell out the chair and on the ground. He wasn't armed. He didn't have a gun. He died by himself. He died alone.

Phyllis McDole

Ms McDole added she didn't "have money to bury my son, this was all of a sudden".

According to Delaware's News Journal, Mr McDole was paralysed from the waist down after being shot in the back around a decade ago.

He lived in a nearby nursing home and was described by his brother, Ashely Morrison-Wright, as a "very, very sweet man".

A local civil rights leader also called for an independent investigation into the shooting, saying police should not be allowed to investigate officers in the same area.

We can’t treat poor folks the way we’ve been treating them.... They have a right to live. They have a right to breathe.

State NAACP President Richard Smith

The four officers involved in the shooting, who have not been named, have now been placed on administrative leave.

After Ms McDole interrupted a police briefing on the shooting calling for "answers", Wilmington police chief Bobby Cummings said the incident and the way it was handled would be investigated.

"I assure you that not one of those officers intended to take anyone's life that day," he added.