Anyone driving past the California Medical Facility in Vacaville on Feb 17, 2016, wouldn’t likely have known the triumph one man was celebrating on the side of the road, just outside the prison’s gates.

“The warden was six years old when I came to prison,” Marvin Mutch said, beaming into the sun and wind. “He came out and shook my hand and said, ‘I really mean this, I’m glad you’re leaving.'”

Mutch waited 41 years for this feeling of freedom.

He’s been in custody since he was 18 years old — a state prison inmate since 19 — for a crime he swears he didn’t commit. The timing of his incarceration, along with other factors about his case, placed him on a parallel track with a four-decade evolution in California criminal justice. It took a massive change in the state’s prison and parole systems for Mutch to be released.

He was convicted solely on circumstantial evidence for the murder of 13-year-old Cassie Riley in 1975. Riley’s death has followed Marvin for his entire adult life, a lifetime spent entirely in prison.