I'd like to know JUST WHAT & WHO SPECIFICALLY THE FBI wants us to keep an eye out for? For example, if these were clearly bearded, stealthy towel heads, and the FBI knew it, would they give us a specific description along that line to narrow it down and clue us in? or would they be politically correct and just keep it vague so nobody's feeeeeeeelings are hurt???
The fact that no physical descriptions are mentioned probably answers your question.