WASHINGTON -- Federal investigators have detained a man they believe was a roommate of at least two of the Sept. 11 hijackers last summer, a U.S. official said Tuesday.
Rasmi Al-Shannaq, a Jordanian citizen, was taken into custody Monday for overstaying his visa, said the official.
On Monday, the State Department's diplomatic security service and the FBI raided a house in Baltimore looking for Al-Shannaq. He was questioned about what he knew of the hijackers and plans they might have discussed.
The official would not say where Al-Shannaq was being held. The men he lived with in the Washington suburbs -- Hani Hanjour and Nawaq Al-Hazmi -- are suspected of hijacking American Airlines Flight 77 just before it was crashed into the Pentagon.
The FBI is still searching for other men believed to have had close contact or lived with the hijackers, the official said.
The official said the government's interest in Al-Shannaq may never lead to charges, but investigators want to know if he might have heard something that would lead to other possible terrorist plans.
The government has argued it may hold immigration violators without releasing information if their arrest has to do with terrorism.
Earlier this month, the Justice Department said 73 people were being held in federal custody on criminal charges or violations related to the government's investigation of Sept. 11. In addition, 74 others were being held on immigration-related charges.