For nearly three decades, Missouri man Lamar Johnson sat in prison serving a life sentence for a murder that he never committed. This week, a St. Louis judge overturned Johnson’s conviction and ordered him to be released from prison.

Upon hearing the news, Johnson was overwhelmed with emotion, as were others watching in the courtroom. Audience members including relatives and civil rights activists jumped up to cheer Johnson attaining his freedom.

“I can’t say I knew it would happen, but I would never give up fighting for what I knew to be the right thing, that freedom was wrongfully taken from me,” Johnson said, telling the Associated Press, “It’s persistence” that led to his exoneration.

It wasn’t just his legal team that helped secure his amnesty. Johnson himself sought out witnesses and other people who would corroborate his story and prove his innocence.

“You have to distinguish yourself. I think the best way to get [the court’s] attention, or anyone’s attention, is to do much of the work yourself,” Johnson said. “That means making discovery requests from law enforcement agencies and the courts, and that’s what I did. I wrote everybody.” Through his own investigations, Johnson contacted people “who were willing to come forward and tell the truth.”

Johnson was 20 years old when he was arrested in 1994 and charged with the homicide of his friend Marcus Boyd. Police and prosecutors claimed that Johnson killed Boyd over drug money. He was sentenced to life in prison without parole in 1995, spending nearly three decades behind bars.

The now-49-year-old insisted he was innocent from the beginning. His alibi was that he was with his girlfriend when the crime happened, which she herself confirmed. The case against him was largely built around an eyewitness who picked him out of a police lineup and an informant in jail who told police he overheard Johnson discussing the crime.

What’s more, the actual killer in the case came forward and admitted their guilt. James Howard, an inmate at South Central Correctional Center in Licking, Missouri is currently serving a life sentence for an unrelated murder and confessed to St. Louis Circuit Judge David Mason that he and another man were the shooters, effectively clearing Johnson’s name. After reviewing the facts, Mason announced his ruling Tuesday (Feb. 14).

“It felt like a weight had been lifted off me,” Johnson said after his long-awaited release. “I think that came out in how emotional I got afterward. I was finally heard.”