The death of Tyre Nichols has provoked outrage and prompted state and federal investigations in the weeks since Mr. Nichols, a 29-year-old Black man, died after being pulled over by the police in Memphis.Lawyers for Mr. Nichols’ family said video footage that has yet to be publicly released shows that he was beaten by police officers for three minutes during the traffic stop. “He was a human piñata for those police officers,” one of the lawyers said. “Not only was it violent, it was savage.”Here is a timeline of the major events in the case:Jan. 7: Around 8:30 p.m., Mr. Nichols was stopped by police officers on suspicion of reckless driving near the intersection of Raines Road and Ross Road in Memphis.The Memphis police said in an initial statement that a “confrontation occurred” as the officers approached his vehicle and that Mr. Nichols ran away. The police said there was then “another confrontation” as officers arrested him, and that an ambulance was called after he complained of shortness of breath.Jan. 10: The Tennessee Bureau of Investigation announced that Mr. Nichols had “succumbed to his injuries” and died.Jan. 14: Mr. Nichols’s family held a memorial event and released a balloon in his honor, according to the Commercial Appeal, a Memphis newspaper. Supporters held a protest at a nearby police precinct.Jan. 15: The Memphis Police Department announced that internal administrative investigations were underway.Jan. 16: Mr. Nichols’ family retained the prominent civil rights attorney Ben Crump, who has represented the families of several Black victims of police violence, including Michael Brown, Breonna Taylor and George Floyd. Mr. Crump called for Memphis police to release body camera footage of the encounter: “Nobody should ever die from a simple traffic stop — the footage is the only way to discern the true narrative of why and how that happened to Tyre.”Jan. 18: The U.S. Department of Justice announced that it had opened a civil rights investigation into Mr. Nichols’s death and was coordinating with the F.B.I.’s Memphis field office.Jan. 20: The Memphis Police Department said five officers had violated department policies in connection to Mr. Nichols’ death, including policies governing excessive use of force, duty to intervene and duty to render aid. All five officers were fired.Jan. 23: Mr. Nichols’s family watched the body camera footage from the night of the traffic stop, but Mr. Nichols’s mother was unable to watch the entire video. Lawyers for the family called the video “disgusting,” likening it to the one showing how Rodney King was brutalized by Los Angeles police in 1991. “How are we here again so many years later?” they asked in a statement.Jan. 24: Preliminary findings of an autopsy commissioned by Mr. Nichols’s family showed that he “suffered extensive bleeding caused by a severe beating.” His family shared a photo taken before he died on Jan. 10 that showed him in a hospital bed, apparently unconscious, his face bruised and swollen.The Memphis Fire Department announced that two employees involved in Mr. Nichols’ “initial patient care” were being “relieved of duty” pending an internal investigation.Jan. 25: The Memphis police chief, Cerelyn Davis, condemned the police officers’ actions as “a failing of basic humanity” in a video statement. Other Memphis police officers were still under investigation for policy violations, she said.Noting the “significant public interest” in the release of the video, the U.S. attorney for the Western District of Tennessee also urged citizens to react in a “peaceful and non-violent way.”Jan. 26: The five fired police officers were arrested in connection with Mr. Nichols’s death and charged with second-degree murder, among other felony charges.Video of the incident will be released after 6 p.m. on Friday, said Steve Mulroy, the Shelby County district attorney, as Memphis braced for what has repeatedly been described as brutal footage.