Anyone can send that kind of email. Have you heard of the term 'impersonation'?
God has given you something between your ears to think. Use it. Having said, I donot deny that there are brainwashed Muslims who can be lured into terrorism but that is a result of indoctrination. Do you know that US government has funded 'research' in ways to indoctrinate Msulims to commit jihad where special recruiters are trained to prey on misguided and angry Muslim youths. One way to make Muslims angry is to keep publishing news articles about 'opression' of Muslims. You will be surprised how easy it is to get converts who are ready to blow themsleves.
