The US Justice Department has announced that it will review the Memphis Police Department policies on use of force, de-escalation policies and specialised units in response to the fatal beating of Tyre Nichols during an arrest.

The review was requested by the city’s mayor and police chief.

In a separate effort, the department will examine the use of specialised units around the country and produce a guide for police chiefs and mayors on their use.

“In the wake of Tyre Nichols’s tragic death, the Justice Department has heard from police chiefs across the country who are assessing the use of specialised units and, where used, appropriate management, oversight and accountability for such units,” said associate attorney general Vanita Gupta.

The US Justice Department has previously opened a civil rights investigation into Mr Nichols’ death.

The city on Wednesday had planned to release about 20 hours of video and audio related to the arrest of the 29-year-old motorist who died on January 10, three days after his violent arrest.

Chief legal officer Jennifer Sink mentioned the video release during a city council committee meeting on Tuesday.

But the release was put on hold on Wednesday after a judge granted a motion to delay from defence lawyers for five officers – Tadarrius Bean, Demetrius Haley, Desmond Mills Jr, Emmitt Martin III and Justin Smith- who are charged over Mr Nichols’ death.

The judge ordered that any release of video, audio, reports and city of Memphis employees personnel files related to the Nichols investigation, including the results of administrative hearings, must wait “until such time as the state and the defendants have reviewed this information”.

It will add to the already-public footage from police body cameras and a surveillance camera that has given the world a detailed look at the police beating Mr Nichols.

Officials have named six officers who have already been fired in the case, and five of them face second-degree murder charges.

Those five officers’ own body cameras recorded them attacking Mr Nichols, propping the badly injured man in handcuffs against an unmarked police car, and then ignoring him as he struggled to stay upright. They have pleaded not guilty.

The six officers previously fired for their roles in Nr Nichols’ arrest and beating were members of the Memphis police’s Scorpion unit, an anti-crime task force that residents have accused of violent tactics.

Memphis Police director Cerelyn “CJ” Davis initially defended the unit after Mr Nichols’ death but later disbanded it. Officers who were part of the Scorpion unit but were not fired have been moved to other units, she said.

Police said Mr Nichols was suspected of reckless driving when he was arrested on January 7 but no verified evidence of a traffic violation has emerged in public documents or in video footage.

Ms Davis has said she has seen no evidence justifying the stop or the officers’ response.

Discipline for those involved in the arrest has extended to the Memphis Fire Department and the Shelby County Sheriff’s Office, where two deputies have been suspended.

The fire department said two of them “failed to conduct an adequate patient assessment of Mr Nichols” while the third, a lieutenant, remained in the fire engine with the driver.