The FBI begins an investigation of an unnamed person for ties to important al-Qaeda figures and several organizations linked to al-Qaeda. The FBI is concerned that this person is in contact with several experts in nuclear sciences. After 9/11, the FBI determines that hijacker Marwan Alshehhi had contact with this person on the East Coast of the US. This person also may have ties to Mohamed Atta’s sister. Most additional details about this person, including his/her name, when and how often Alshehhi had contact, and if the investigation was ever closed, remain classified. [US Congress, 7/24/2003 ]