My father is a retired corrections officer who worked inside a prison for more than 20 years. Most days he went to work without incident and he always tried to comfort us by saying that acts of violence behind bars are not nearly as common as most people think. But on one terrible day something happened that showed us just how dangerous his workplace could be. Without warning an inmate attacked him and left him badly beaten.

It took a long time for him to recover. But he eventually went back to work in the same prison, surrounded by the same inmates. Nothing like that ever happened again (thankfully), but my dad was never able to comfort us any more by pointing out how that attack was the exception for prison life and not the rule.

That traumatic time for my family was very much on my mind as I heard the loud clank of the heavy metal doors behind me at California's infamous Folsom Prison. We had come to ask questions about the potential for a new kind of violence and those new exceptions that could leave innocent people injured...or worse.

A special report from two major universities warned of a global trend of men going into prison as criminals and coming out transformed into religious and political radicals. Shoe-bomber Richard Reid is believed to have been influenced by a radical Imam while in a British prison. In the United States, California inmate Kevin James allegedly founded his own radical Islamic group and directed a failed terrorist plot, all from behind bars. (James pleaded innocent to charges of conspiracy to wage war against the U.S. government and other charges, and is awaiting trial.)

At Folsom, we found that there is indeed concern that today's overcrowded and understaffed prisons could be an incubator for terrorism. Some officials say it is the perfect environment for someone with radical ideas to stoke the flames of hatred and give rise to a wave of homegrown terrorists. Prison officials compare this "radicalization" of inmates to gang activity saying it is impossible to stop and difficult to manage.

Religious converts behind bars (and there are a lot of them) are said to be prime targets. And while converts of any religion could be at risk, the universities' report says those new to Islam could be more vulnerable than others. That's because prisons like Folsom don't always have a qualified, full-time chaplain to lead services and teach. This could give a motivated inmate the opportunity to spread his own radical ideas to a captive audience.

Imam Salem Mohamed, a prison chaplain, has to split his time between inmates at Folsom and one other prison. He is available to the prisoners for only five days every other week. In ten years, he says, he has only encountered a few inmates with radical ideas. The vast majority he says follows the call to prayer seeking peace, many trying to escape a life of violence. But the authors of this report say all it takes is one charismatic figure to take advantage of this vacuum and sow the seeds of jihad.

It's important to note that followers of Islam are a small minority in a large prison population. Those with radical religious ideas (of any faith) are believed to represent a much smaller minority than that. The odds that one of them might actually cause harm to innocents seems remote. And had it not been for my own family's experience...I might have found that comforting.