He was inspired by MLK's "I Have A Brooch" speech.
Sandifer robbed six stores and exchanged his illicit bounty for licit cash that he donated to the cause. And some of these were real Hollywood-style capers: On one job, Sandifer and his driver plotted and timed their getaway route so perfectly that they flew through a train crossing just as the train came by, leaving the police on the other side, shaking their fists and stomping on hats in consternation.
"And I didn't need any damn NOS!"
But apparently it's easier to steal jewelry than it is to sell it, as Sandifer was caught pawning off his latest acquisitions and did 16 months in jail. After he was released, his identity remained unknown for 50 years until a newspaper tracked down the "Robin Hood for the Civil Rights Movement." They discovered that he had been living near the poverty line ever since, in order to legally support civil rights, gay rights, senior citizens, and people with HIV/AIDS. Or perhaps he just got really, really good at charitable cat-burglaring and nobody ever caught him again. That's how our screenplay has it, anyway.