DENVER - An inmate in handcuffs and shackles jumped through a closed window in a third-floor courtroom, shattering the glass, plunging to the ground and critically injuring himself, police said Wednesday.

The man, in court on a misdemeanor assault charge, had been told to go before the judge at the Denver City and County Building, a witness said. "And he was just sitting there, turned around and he went headfirst out the third-story window," Ty Berrien told KCNC-TV in Denver.

It wasn't immediately clear whether Josephus Haynes' goal was escape or suicide, police said.

Haynes was in critical condition, authorities said. He was lying on a grate outside the building when emergency workers arrived, said Fire Lt. Phil Champagne.