Demetrius Haley allegedly took part in a 2015 incident at a county prison that resulted in an entire cellblock writing a letter to the corrections director

Years before Memphis police officer Demetrius Haley pulled Tyre Nichols from his car on 7 January, setting in motion a deadly confrontation, Haley was accused of taking part in the savage beating of an inmate at a county prison.

The 2015 assault of the inmate was so disturbing that 34 others – the entire cellblock – signed a letter to the corrections director.

Investigation finds Preston Hemphill violated rules regarding stun gun use, and video shows him saying ‘I hope they stomp his ass’

A sixth Memphis officer was fired on Friday after an internal police investigation showed he violated multiple department policies in the violent arrest of Tyre Nichols, including rules surrounding the deployment of a stun gun, officials said.

Preston Hemphill had previously been suspended as he was investigated for his role in the arrest of Nichols, who died three days later. Five Memphis officers have already been fired and charged with second-degree murder in Nichols’s death.

The Scorpion unit has been deactivated after video was released of the brutal beating of the 29-year-old at the hands of officers

• This article contains a video depicting violence

The Memphis police chief on Saturday disbanded the unit whose officers beat to death Tyre Nichols as the nation, citing a “cloud of dishonor”, as the city struggled to come to grips with video showing police pummeling the Black motorist.

Police director Cerelyn “CJ” Davis said she listened to Nichols’ relatives, community leaders and uninvolved officers in making the decision.

The grisly footage, released in four parts, indicates an ambulance did not arrive for more than 20 minutes after the vicious beating

• This article contains video and descriptions of physical violence

A group of Tennessee police officers punched and kicked Tyre Nichols –delivering at least a half-dozen blows – as he languished on the ground, crying out for his mother, during a 7 January beating that would result in his death, surveillance footage released on Friday night revealed. The deadly attack on Nichols reportedly unfolded about 80 yards from his mother’s home.

The disturbing video, which was released in four parts by the Memphis police department, included both body-camera and street lamp-mounted camera video showing the attack on Nichols, who is Black. While Nichols’s injuries were clearly severe, and his physical condition in obvious decline, the video indicates that an ambulance did not arrive for more than 20 minutes after the vicious beatdown.