After serving nearly 50 years in prison for a murder he did not commit, a 71-year-old man in the US state of Oklahoma has been declared innocent.

The National Registry of Exonerations states that the Black inmate, Glynn Simmons spent the longest time of incarceration before being declared innocent in US history.

“This court finds by clear and convincing evidence that the offense for which Mr. Simmons was convicted, sentenced and imprisoned… was not committed by Mr. Simmons,” according to the ruling by Oklahoma County District Judge Amy Palumbo.

Simmons was released in July after serving a total of 48 years, one month and 18 days in prison.

Simmons and another man, Don Roberts, were sentenced to death in 1975 for the murder of a 30-year-old liquor store clerk during a robbery in Edmond, Oklahoma. Their sentences were later reduced to life in prison in 1977.

Simmons has maintained his innocence, saying he was in Louisiana at the time of the 1974 slaying of Carolyn Sue Rogers inside an Edmond liquor store.

The testimony of a teenage customer who was shot in the head during the heist but survived, served as the only basis for Simmons and Roberts’ conviction.

The teenage identified them from a police lineup, however the validity of her identifications was seriously questioned after an inquiry.

Simmons told reporters on Tuesday that, “This is a day we’ve been waiting on for a long, long time. We can say justice was done today, finally.”

Roberts, Simmons’ co-defendant, was released from prison in 2008, according to the National Registry of Exonerations.

The ruling makes Simmons eligible for up to $175,000 in compensation from the state for wrongful conviction.

“What’s been done can’t be undone but there could be accountability,” he said. “That’s what I’m about right now. Accountability.”