Another thing to look for are indentions and markings on the foreheads of men who look like the type that may be a problem.
The markings come from their heads hitting the floor five times a day when they "pray".
re: the prayer bump. You can see the beginning of one on umar the pantybomber's forehead. I would have profiled him on the basis of this alone
umar without prayer bump.
umar with the beginnings of a prayer bump