Tyre Nichols: What is the 'Scorpion' unit of Memphis police?

Some of the five ex-officers in Memphis charged with the murder of Tyre Nichols were part of an elite crime-fighting unit that is now under scrutiny.

Scorpion - which stands for "Street Crimes Operation to Restore Peace in Our Neighborhoods" - is a 50-person unit with the mission of bringing down crime levels in particular areas.

The police chief has now ordered a review of all specialised police units.

This is not the first time the Scorpion unit has attracted controversy.

It was launched in October 2021 with a focus on high-impact crimes such as car thefts and gang-related offences.

But some community activists say its focus on hot spots within the city contributes to officers' bias and brutality.

Antonio Romanucci - a lawyer for the family of Mr Nichols, who was black - accused the unit of misconduct in the latest incident.

"They were in unmarked cars, why are they conducting traffic stops?" he told CBS, the BBC's US partner.

"This is a pretextual traffic stop, which, let's call it what it is, it's a racist traffic stop."

It remains unclear how many of the officers, who are all black, were part of the Memphis Police Department's Scorpion unit.

"The Scorpion unit was involved," Shelby County District Attorney Steve Mulroy said on Thursday at a news conference as he announced the charges against the fired officers.

Memphis Police Chief Cerelyn Davis, the first black woman to serve in that role for the city, said before charges were filed in the Tyre Nichols case that the Scorpion unit - and all specialised police units - would undergo a review.

The Scorpion programme was touted by Memphis Mayor Jim Strickland in a speech a year ago. He said the city used crime data "to determine where the unit will conduct its enforcement activities within the city".

From October 2021 until January 2022, the unit made 566 arrests, he said. They also seized over $100,000 in cash, 270 vehicles and 253 weapons.

In the wake of Mr Nichols' death, local man Cornell McKinney told a TV network he had a tense encounter with the unit on 3 January, just days before the incident involving Mr Nichols.

Mr McKinney alleges that the officers - who were travelling in unmarked vehicles - threatened to "blow his head off", pointed a weapon at his head and accused him of carrying drugs.

He complained to the Memphis Police Department after the incident, but says he had not heard anything back.

One of the officers that arrested Mr Nichols had previously been sued by a man who accused him of beating him when he was a prisoner eight years ago.

Cordarlrius Sledge said that he was attacked by Demetrius Haley, who was a prison guard at the time, and two other officers after he was found with a contraband mobile phone in jail.

"They picked me up and slammed my head into the sink, and I blacked out," he told NBC News on Thursday.

The lawsuit was dismissed in 2018 after a judge found the prisoner had failed to complete the necessary legal paperwork.