The radical American-born Muslim cleric who inspired the terrorists behind the Charlie Hebdo attacks spent thousands of dollars on prostitutes while travelling the United States.

Anwar al-Awlak used prostitutes at least seven times in the Washington D.C. area between November 2001 and February 2002, according to leaked FBI documents.

He met brothers Cherif and Said Kouachi as they trained in the deserts of Yemen where al Qaeda's deadliest franchise, AQAP, is based.

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Paying for sex: Anwar al-Awlaki is said to have used prostitutes at least seven times in the Washington D.C. area between November 2001 and February 2002, according to leaked FBI documents

The hate preacher met brothers Cherif (left) and Said Kouachi (right) as they trained in the deserts of Yemen where al Qaeda's deadliest franchise, AQAP, is based

The cleric, who was killed in a U.S. drone strike in September 2011, is believed to have spent $2,300 on hookers in Washington alone.

Another prostitute told the FBI that al-Awlaki paid her $300 to watch as 'as she engaged in erotic behavior and stimulated herself' in December 2001 and again in January 2002.

One hooker told FBI agents 'she looked through the 'peep' hole ... and thought to herself that he looked like Osama bin Laden.

Al-Awlaki, who was born in New Mexico, reportedly paid $400 to have sex with the woman. She described him as 'very polite.'

It appears the married father of five had a history of paying for sex, despite his deeply fundamentalist beliefs.

History: One prostitute told the FBI that al-Awlaki paid her $300 to watch as 'as she engaged in erotic behavior and stimulated herself'. He was also arrested twice in San Diego for soliciting

He was also arrested in 1996 and 1997 for soliciting prostitutes in San Diego where he worked at a small mosque. He pleaded guilty and paid a fine.

The Kouachi brothers were trained for three days in the deserts of Marib on how to fire a gun. They returned to Oman and they left Oman on August 15, 2011 to go back to France.

They were shot dead by French security forces after they took refuge in a print works outside Paris.