Why FBI didn't act against Awlaki in US despite knowing about his terrorist activities

The Federal Bureau of Investigation was well aware of radical American Muslim cleric Anwar al-Awlaki's movements, raising questions about why more was not done to detain him.

Outgoing FBI Director Robert Mueller was deeply involved in the post-9/11 handling of Awlaki, the first American targeted for death by the CIA, according to newly released documents reviewed exclusively by Fox News.

The documents, marked 'Secret' and titled 'Anwar Aulaqi: IT-UBL/AL-QAEDA', released after Judicial Watch, a conservative watchdog group, filed a Freedom of Information Act request and then sued the FBI, show a memo from Mueller to then-Attorney General John Ashcroft on Oct. 3, 2002.

According to the report, national security defense attorney Edward MacMahon Jr., after reviewing the documents, said that they certainly indicate that either Awlaki was an asset or was put in touch with an asset.

It was reported in 2010 that the Justice Department suddenly pulled the arrest warrant for Awlaki, the same week he returned to the U.S. from overseas.

The Justice Department, explaining why it had pulled the warrant, claimed Awlaki had corrected lies about his place of birth on his Social Security card application, in turn making a passport fraud case against him weak.

Based on new documents, there are at least three possible explanations for Awlaki's return and the FBI's considerable involvement.

According to the report, the bureau was attempting to recruit him as an asset, he was already considered a friendly contact or the bureau wanted to track him for intelligence purposes once he returned to the U.S.

The FBI's involvement in Awlaki's case, and the actions of the FBI director, raise new questions about the secret decision to place the cleric on the CIA targeting list years later, the report added.