DETROIT — A man awaiting sentencing in an armed robbery was on the run Monday after stabbing a sheriff’s deputy several times in the neck, stealing his uniform then carjacking a motorist in a daring escape from a downtown Detroit courthouse, authorities said.

The escape by Derreck White, 25, who police said also used the name Abraham Pearson, sparked a manhunt and prompted a lockdown of the Frank Murphy Hall of Justice.

White overpowered Deputy Harrison Tolliver as he transported White and two other prisoners to a holding cell, Wayne County Sheriff Benny Napoleon said. White stabbed the deputy with a plastic comb that had been fashioned into a shank, Napoleon said.

“It was very quick,” Napoleon said. “He overcame the deputy, took his clothing, got on the elevator and escaped.”

Napoleon described the deputy’s injuries as “puncture wounds,” but said he is fine.

White was scheduled to be in court this morning to learn his punishment after being convicted last month of carjacking, armed robbery and firearms charges, according to court records.

White’s defense attorney, James Howarth, said he has a history of mental illness but was found competent to stand trial.