Matter of fact I bet there are more people in prison that don't believe in God than do. I'm gonna do some research on it and get back to you on that one. A lot of prison reform does occur when the prisoner accepts God into his/her life, supporting the claim that believing in God is not a bad thing.
Sorry, junebug, but the facts don't bear this out. Very few atheists commit crimes. And belief in god does not make people behave. The vast majority of US prisoners are god-believers. Also, lower income folks are much more likely to believe in god and
to end up in jail. Correlation, but not necessarily causation.....
There are many reasons people in jail "take god into their hearts" but in my experience the main ones are: even with the cutback in social services like drug treatment and anger management to prisoners, religious groups (like bible study) are still offered; going to religious services is one way to get out of your cell for an hour or two; regular attendance at religious services looks good at parole hearings; bibles, Qurans and other religious books are freely available and unrestricted by law.
So, it may not be that god caused the prisoner to reform. But humans who think that god caused the prisioner to reform are more likely to let him/her out of jail. The high re-arrest and re-incarceration rates suggest that god needs to try a bit harder with prisoners.
Or maybe god should just stay out of it. The regions of the US with the highest levels of belief in god have the highest crime rates and largest prision populations. Also the highest teen pregnancies, divorce rates, family violence rates, unemployment and poverty rates.
The same thing holds around the world. The countries with the lowest levels of god-belief, regardless of religion, are the safer, nicer places to live with the lowest crime rates, highest education rates, best health care stats, lowest infant mortality rates, etc. Japan and Denmark are two examples of very successful countries where almost nobody believes in any gods.