From the time he was a young boy, Casey Diaz watched his father assault his mother on a regular basis.  He witnessed a triple homicide by the time he was eight.  By age eleven he was in a Los Angeles-area gang and five years later he was a gang leader on his way to prison for killing a rival gang member.

That's the bleak beginning to Casey's life but it also sets the stage for his dramatic transformation, which he recounts in the new book "The Shot CallerCasey's life appeared hopeless.  He was staring at a long prison sentence that he had no qualms about serving because it was expected of gang members.  He was thoroughly unrepentant.  

Then Frances Proctor walked in his prison.  Proctor was a tiny lady from a nearby Baptist church who faithfully came to pray for and evangelize the prisoners.  Corrections officers told her she would be wasting her time on Casey Diaz.  

Proctor didn't listen to them. 

At first, Casey politely told Proctor he wasn't interested in her message.

"She had the boldness of a lion.  I remember her telling me, 'I'm going to pray for you and Jesus is going to use you,'" said Diaz, who is author of "The Shot Caller," which tells the story of his dramatic conversion.

For the next 18 months, Proctor visited Diaz once a month and assured him each time she was praying for him.

"I would spend maybe two to four minutes with her and she was just giving me the love of Christ and talking to me," said Diaz, who says Proctor's intercessory prayers led to him surrendering his life to Jesus one night in his cell.

"There was something so authentic about her concern for inmates in there and for some reason she just zeroed in on my life," said Diaz.

Listen to the full podcast to hear how Casey's life changed after that, how he soon became a target in prison, how he connected with Proctor after getting out of prison, and what he thinks are the best ways to reduce gang violence.