WASHINGTON (AFP) - A video of an incident in which US police officers repeatedly used a stun gun to subdue a mentally ill inmate who eventually died from the encounter was released on Thursday (Sept 10).

Earlier this week, the officers were found to have not committed any crimes in the Feb 3 incident, in which Natasha McKenna was shocked four times, stopped breathing and died in a hospital five days later.

Sheriff Stacey Kincaid of Fairfax County, Virginia, said she made the decision to release the footage because the investigation into the officers' actions had ended.

"From the outset of this terrible tragedy, I promised to cooperate fully with the investigators and to be transparent about the incident involving Natasha McKenna," Sheriff Kincaid said.

"I am fulfilling my promise to release the complete video and all of the incident reports related to Ms McKenna's incarceration."

The video shows McKenna, 37, struggling as officers in biohazard suits, who said she had urinated and defecated in her cell, attempted to move the inmate to a different prison.

"You promised me you wouldn't kill me. I didn't do anything," McKenna says before a graphic struggle in which the officers eventually shock her with Taser stun guns.

She stops breathing soon after.

The video alarmed mental health advocates and McKenna's family.

Mr Harvey Volzer, attorney for McKenna's family, disagreed with the earlier finding that McKenna's death was a result of "excited delirium" and which cleared the officers of wrongdoing.

"What caused her death was one officer using a Taser four times on a completely helpless, mentally impaired female in violation of rules governing the proper use of a Taser, and seven additional officers doing nothing to intervene," he told The Washington Post earlier this week.