By Daniel Trotta and Julia Harte
(Reuters) -Fired Memphis police officer Desmond Mills pleaded guilty on Thursday to federal charges in the death of Black motorist Tyre Nichols and has agreed to plead guilty to related Tennessee state charges, prosecutors said.
Mills was one of five officers to have previously pleaded not guilty to federal civil rights offenses and state charges of second-degree murder.
But Mills has now agreed to cooperate with prosecutors in both the state and federal cases, the office of Shelby County District Attorney Steve Mulroy said in a statement, raising the possibility he may testify against his former fellow officers.
In exchange, Mills, who was facing life in prison, is now looking at a sentence of 15 years, as agreed to by state and federal prosecutors, the statement said, though a judge will make the final determination on sentencing.
The case is one of a series raising the national debate about racism and police brutality in the United States.
Police video showed the officers kicked, punched and pepper-sprayed Nichols and struck him with a baton on Jan. 7.
At one point, officers held him so another could punch him in the face, while at other times Nichols cried out for his mother, who lived nearby.
Nichols, 29, died in hospital three days later.
Mills was one of five officers, all Black, charged with two federal civil rights counts of excessive force plus two witness-tampering counts. He pleaded guilty to one count of each.
Mills and the other fired officers - Demetrius Haley, Emmitt Martin III, Justin Smith and Tadarrius Bean - were also charged with second-degree murder and other counts in Shelby County. A hearing in that case is scheduled for Monday.
Mulroy's office did not say whether Mills would testify against the other defendants as part of the deal. Mills' defense attorney, Blake Ballin, did not respond to requests for comment on whether Mills planned to do so.
But civil rights lawyer Ben Crump and his colleague Antonio Romanucci, representing Nichols' family, called Mills' decision to cooperate historic.
"This is a monumental shift in policing today, watching another police officer who will testify against his own," Romanucci told reporters, the Daily Memphian reported.
In video of the aftermath of the beating, the officers alleged Nichols was driving erratically and evaded arrest.
According to the plea agreement filed in federal court, Mills later admitted to violating police policy and training by using unjustified force and failing to provide necessary medical aid.
Mills pepper-sprayed Nichols three times and stuck him with a baton in violation of police training, then "did nothing to stop the assault by his fellow police officers," the agreement said.
Mills also removed his body-worn camera afterward so he could speak with other officers without being recorded, the document said.
"My use of force was excessive and I gave misleading statements," Mills told Judge Mark Norris in Thursday's hearing, according to the Memphis Commercial Appeal.
(Reporting by Daniel Trotta in Carlsbad, California, and Julia Harte in New York; Editing by Rod Nickel)