I recall numerous threads on prison converts eight or ten years ago. But I guess the best they’ve put out so far was a shoe bomber, so the controversy died down. Placing all of us at risk.
Here's a few quickly found instances of subsequent prison converts committing/planning Jihadi attacks on western "infidels:"
Probe fans fears of prison terror plots {against LA National Guard} - 8/22/2005With a little more time, many others could be found. If you include Europe the list grows even more - starting with one of the attackers in the recent Paris attack kosher supermarket and magazine attack AND the Canadian capital attack.Oklahoma Beheading: Have Our Prisons Become Jihad Factories? - 9/26/2014
And here's the chilling recent estimates of the problem:
one-in-three-blacks-inmates-converts-to-islam-in-prison/