Federal prosecutors recommended a 40-year sentence for a former Memphis police officer who pleaded guilty Friday to civil rights violations in the 2023 fatal beating of Tyre Nichols.

Emmitt Martin is the second former officer to plead guilty in the killing, leaving three officers facing trial in federal court next month with the possibility of their former colleagues testifying against them.

Martin entered his change of plea before U.S. District Judge Mark Norris in Memphis under an agreement with prosecutors, delivering another twist in the case that sparked outrage and calls for police reform. Martin pleaded guilty to excessive force and witness tampering charges. The judge had set a Monday deadline for any plea agreements in the case.

Nichols’ mother, RowVaughn Wells, was in the courtroom. She quietly nodded her head and smiled when the judge accepted Martin’s change of plea.

“The family is relieved that another officer has admitted their role in these heinous acts that killed Tyre Nichols. This is yet another crucial component to getting accountability,” Ben Crump, an attorney for Nichols’ family, said after the hearing.

In November, former Memphis officer Desmond Mills Jr. reached a similar deal with federal prosecutors and changed his plea to guilty. Prosecutors recommended a 15-year prison sentence for Mills.

Both Mills and Martin could be called to testify against the final three —Tadarrius Bean, Demetrius Haley and Justin Smith— who remain charged with federal civil rights violations and have pleaded not guilty.

All five former officers accused in Nichols’ death have been charged separately in state court with second-degree murder. That trial is postponed until the federal proceedings are complete.

Nichols was a 29-year-old father from Sacramento, California. He worked at FedEx with his stepfather and enjoyed skateboarding and photography in his spare time.

Nichols died in a hospital on Jan. 10, 2023, three days after he was kicked, punched and hit with a police baton after a traffic stop. The officers said they pulled Nichols over because he was driving recklessly, but Police Chief Cerelyn “CJ” Davis has said no evidence was found to support that allegation.

Police video released Jan. 27 showed five officers beating Nichols as he yelled for his mother about a block away from the home they shared. Video also showed the officers milling about and talking with each other as Nichols struggled with his injuries.

Nichols was Black. The five officers also are Black. They were fired for violations of Memphis Police Department policies.

An autopsy report showed Nichols died from blows to the head, and that the manner of death was homicide. The report described brain injuries, cuts and bruises to the head and other parts of the body.

Martin, who was the second officer to come into contact with Nichols during the Jan. 7 traffic stop, helped Haley to force Nichols from his vehicle, according to documents filed in the case to permanently ban Martin from working in law enforcement in Tennessee.

Nichols ran from Martin and his two partners after they threatened and pepper-sprayed him, but he was apprehended within six minutes. As other officers tried to handcuff Nichols, who was on the ground, Martin kicked him in the upper torso and punched him in the face while two other officers held Nichols’ arms, the documents show.

The criminal charges are separate from the U.S. Department of Justice’s “patterns and practices” investigation into how Memphis officers use force and conduct arrests, and whether the department in the majority-Black city engages in racially discriminatory policing.

The Justice Department also has announced a separate review concerning use of force, de-escalation strategies and specialized units within the Memphis police.

Additionally, Nichols’ mother has filed a $550 million lawsuit against the city and its police chief.