ST. PAUL — A federal judge on Thursday sentenced Derek Chauvin to 21 years in prison for violating George Floyd’s civil rights, telling the former Minneapolis police officer that what he did was “simply wrong” and “offensive.”

U.S. District Judge Paul Magnuson sharply criticized Chauvin for his actions on May 25, 2020, when the white officer pinned Floyd to the pavement outside a Minneapolis corner store for more than 9 minutes as the Black man lay dying. Floyd’s killing sparked protests worldwide in a reckoning over police brutality and racism.

“I really don’t know why you did what you did,” Magnuson said. “To put your knee on a person’s neck until they expired is simply wrong. … Your conduct is wrong and it is offensive.”

Magnuson, who earlier this year presided over the federal trial and convictions of three other officers at the scene, blamed Chauvin alone for what happened. Chauvin was by far the senior officer present, and rebuffed questions from one of the others about whether Floyd should be turned on his side.

“You absolutely destroyed the lives of three young officers by taking command of the scene,” Magnuson said.

Even so, Magnuson’s sentence was at the low end of the 20 to 25 years called for in a plea agreement in which Chauvin will serve the federal sentence at the same time he serves his 22 1/2-year sentence on state charges of murder and manslaughter.

Because of differences in parole eligibility in the state and federal systems, it means that Chauvin will serve slightly more time behind bars than he would have on the state sentence alone. He will also do his time in the federal system, where he may be safer and may be held under fewer restrictions than in the state system.

Chauvin attorney Eric Nelson had asked for 20 years, arguing that Chauvin was remorseful and would make that clear to the court. But Chauvin, in brief remarks, made no direct apology or expression of remorse to Floyd’s family.

Instead, he told the family that he wishes Floyd’s children “all the best in their life” and that they have “excellent guidance in becoming good adults.”

In entering his federal plea last year, Chauvin for the first time admitted that he kept his knee on Floyd’s neck — even as the Black man pleaded, “I can’t breathe,” and then became unresponsive — killing Floyd. Chauvin admitted he willfully deprived Floyd of his right to be free from unreasonable seizure, including unreasonable force by a police officer.

Magnuson has not set sentencing dates for the three other officers who were on the scene — Tou Thao, J. Alexander Keung and Thomas Lane — who were convicted in February of federal civil rights charges.

Lane is also due to be sentenced Sept. 21 after pleading guilty in state court to aiding and abetting second-degree manslaughter. Thao and Kueng turned down plea deals and are due to be tried in state court Oct. 24 on aiding and abetting charges.