The prosecution's case was built largely on FBI wiretaps and fax transmissions gathered between 1994 and the time of Mr. Al-Arian's arrest in 2003. The surveillance included roughly 20,000 hours of dialogue from 472,000 wiretapped telephone conversations on 18 tapped lines gathered from 1994 to 2003.[77] While such wiretaps taken by the intelligence arm of the FBI are usually kept secret from federal criminal investigators, provisions in the Patriot Act and the Foreign Intelligence Surveillance Act allow their use in certain trials dealing with terrorism.[78] At the end of the prosecution's case, Al-Arian's lawyers chose not to present any witnesses in his defense and rested without offering a defense, hoping to leave the burden of proof squarely on the government's shoulders.[79] The trial concluded in November 2005.