NEW YORK

David Jassy was a successful music producer who had worked with Britney Spears and others when he was sent to prison for killing a man during an altercation. While serving his time, he would hear talented young inmates rapping in the yards at San Quentin State Prison with skill and power. In his cell, where Jassy used his keyboard to make beats, he invited the men to perform rap freestyles and taught them about songwriting and music production.

In the jail’s media center, Jassy uploaded each sound from his keyboard to a computer so he could produce music digitally. Word spread about Jassy’s music-led initiative as part of the prison’s Youthful Offenders Program, and donors — including Grammy-winning producer Greg Wells — contributed audio equipment, transforming the media lab into a full-blown production studio.

Celebrities even got involved, including J. Cole, Kim Kardashian West, Common and MC Hammer — all who visited San Quentin to see Jassy’s efforts and encourage the inmates to keep pushing through.

Now, an album of those songs will be released to streaming platforms on May 29 on Equity Distribution, Roc Nation’s in-house music distribution platform. “San Quentin Mixtape, Vol. 1,” produced by Jassy, features 17 young rappers telling their stories.

“It’s so beautiful when you see the transition from youngsters coming in because a lot of them really act out because they’re either hurt or scared — because you have to keep up a certain facade in prison, you don’t want to show that you soft,” Jassy, who is Swedish, said in an interview with The Associated Press from Stockholm. “For them to basically be vulnerable on a mixtape in prison and really speak their truth, it’s not an easy thing to do.”

Though some rap can be profanity-heavy, Jassy challenged the young performers by telling them curse words were not allowed in the songs.