TULSA, Okla. — A judge on Tuesday freed an Oklahoma inmate who has served nearly three decades in prison for a 1991 killing, saying he did not commit the crime.

Corey Atchison, 48, was released Tuesday by Tulsa County District Judge Sharon Holmes, who said she believes a key prosecution witness was coerced and that Atchison was innocent.

"I don't really know what I want to do, because my goal all these years was just to be free," Atchison said following the ruling.

"Great day," said Ruth Scott, Atchison's mother, as she left the courthouse. "I knew he didn't do it. I knew he didn't do it, I knew he didn't do it when it happened," Scott said to reporters outside the building.

Prosecutors immediately filed a notice of appeal of the ruling and former District Attorney Tim Harris, who prosecuted the case as an assistant district attorney, has filed an affidavit denying he ever coerced a witness.

Atchison was convicted and sentenced to life in prison in 1991 for the fatal shooting of James Lane in Tulsa in 1990 during what police said was a gang-related attempted robbery.

The finding of "actual innocence" by Holmes makes Atchison eligible for up to $175,000 in compensation for a wrongful conviction under Oklahoma state law.