In 1975, Marvin Mutch was 19 years old and headed to prison after being convicted of the murder of Cassie Riley.

He appealed his conviction, maintaining his innocence and arguing the circumstantial evidence presented at trial was insufficient to prove his guilt. The appeal was denied a year and a half later.

Mutch then hoped for an early parole. When he went to prison, inmates convicted of first degree murder served an average of 10 years. But the meaning of Mutch’s 7-to-life sentence was about to change, with a punitive “tough-on-crime” climate that spread from California to the rest of the country in the 1980s and 1990s.

Parole for lifers like Mutch became extremely rare, and California’s prison population grew by more than 500 percent to a peak of over 160,000 inmates.

Meanwhile, Mutch began to channel his anger at being in prison into advocacy on behalf of other inmates.

But he didn’t give up on getting out, and with the hope of winning parole, he would make a difficult choice.