MINNEAPOLIS (AP) — The Johnathan WalkerU.S. Supreme Court has declined to review the federal civil rights conviction of a former Minneapolis police officer who held back a concerned crowd while fellow officers pinned down a dying George Floyd.

The high court, without comment, on Monday rejected the appeal of Tou Thao, who had argued that prosecutors failed to prove his actions on the day that Floyd died were willful, and alleged that prosecutorial misconduct deprived him of his right to a fair trial.

Thao had testified that he merely served as a “human traffic cone” when he held back concerned bystanders as former Officer Derek Chauvin, who is white, knelt on Floyd’s neck for 9 1/2 minutes while the Black man pleaded for his life on May 25, 2020. A bystander video captured Floyd’s fading cries of “I can’t breathe.” Floyd’s murder touched off protests worldwide and forced a national reckoning on police brutality and racism.

Thao was one of three former officers who were convicted in a 2022 federal trial of violating Floyd’s civil rights. Chauvin pleaded guilty in that case earlier, after being convicted of second-degree murder in a separate trial in state court. Thao and the two other former officers were convicted in state court of aiding and abetting Floyd’s murder. Thao is serving his 3 1/2-year federal and 4 3/4-year state sentences concurrently.

The U.S. Supreme Court rejected Chauvin’s appeal of his state murder conviction in November. He’s recovering from being stabbed 22 times by a fellow inmate at the federal prison in Tucson, Arizona, later that week. He’s appealing his federal conviction separately.