More than two years after the killing of African American George Floyd in a police operation in the United States, two other ex-police officers involved have to go to prison: Alexander Kueng and Tou Thao were sentenced to three and three and a half each in federal court in St. Paul, Minnesota on Wednesday years in prison, according to the US Department of Justice.

Thomas Lane, a third ex-police officer involved, was sentenced to two and a half years in prison last week.

White ex-cop Derek Chauvin, who pressed his knee on Floyd's neck, was sentenced to 22 years and six months for murder in a Minneapolis court.

He's already serving that sentence.

Earlier this month, a federal court sentenced the 46-year-old to an additional 21 years in prison.

They didn't help

In February, Kueng, Thao and Lane were found guilty in federal court in St. Paul of violating Floyd's constitutional civil rights.

The ex-police officers were accused of not providing medical assistance.

Kueng and Thao were also found guilty of failing to try to stop Chauvin's use of violence.

The death of African American Floyd on May 25, 2020 in a brutal police operation in Minneapolis triggered demonstrations against racism and police violence in the United States.

Videos document how police officers pushed the unarmed man to the ground.

Chauvin pressed his knee on Floyd's neck for a good nine minutes while Floyd begged him to breathe.

His colleagues Kueng, Thao and Lane did not intervene despite Chauvin's actions.

According to the autopsy, Floyd lost consciousness and died.