I'm don't have the prison mission affiliation that you have, but I wondered about this, and thought the same thing. They seem quite popular in prisons. I'd be curious as to who the Wahhabists target for conversion, given the violent tendencies of some criminals, and the recidivism. Does that work for or against their aims? (I would think both.) It's most telling that of the many 'outreach' and conversion programs, the prison one enjoys big success and is pushed. I mean, it ain't the Amish they're targeting for conversion...
On October 20, 2002, the New York Times quoted Faheem Shuaibe, imam at a large, predominately black mosque in Oakland, Calif., as saying that more than 200 African-American imams have been trained so far in Saudi Arabia.
And they are going to all lengths to indoctrinate and 'train' their recruits.
My opinion on this question is that many terrorists are previous criminals (yes based on personal knowledge) who have found a way to legitimize their behavior in the name of religion. Now they can drink, take drugs, steal, kill....anything in the name of islam and they are beloved by their fellow muslims. If Saudi is converting criminals to Islam then one would think they were interested in these men and their prior behavior, violent tendencies and skills for a reason.