PEMBROKE PINES, Fla. -- The FBI is investigating a death threat made against a Muslim leader in South Florida.

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Altaf Ali said the Council of American-Islamic Relations received a piece of hate mail this week. He said it's happened before but the message has never been a death threat.

The letter said, "Islam is the religion of Satan. Death to Islam."

"I try to do good things and to be rewarded with such messages and threats -- it's emotionally draining," Ali said.

Ali's wife, Jocelyn Pettitt, said she is scared for her husband and her children.

"It kind of puts some fear in the fact that they know who he is, where he works. It must be somebody in the area," Pettitt said.

Ali said he got the letter on Monday. It has writing on the front and cartoon-like drawings with captions on the back.

As the local director of the Council of American-Islamic Relations, Ali said he has gotten hate mail before but never with his name on it.

The first line of the letter reads, "Altaf Ali is a walking dead man."

"I told my husband we should put up shutters in our room," Pettitt said.

"If I put hurricane shutters up that means the people who want to disturb the American way of life have won," Ali said.

FBI agents said the letter Ali received is very similar to one recently sent to the Council of American-Islamic Relations office in Michigan.

Ali's letter had a return address of Illinois and a postmark from Indiana.

"If the person who wrote this letter is looking at us right now, that person will be well aware that the FBI is investigating," Ali said.