The Saudi Interior Ministry on Sunday confirmed it is holding a 21-year-old Saudi man the FBI is seeking for alleged links to the Sept. 11 hijackers.
Authorities are interrogating Saud Abdulaziz Saud al-Rasheed "and if it is proven that he was connected to terrorism, he will be referred to the sharia (Islamic) court," the official Saudi Press Agency quoted an unidentified ministry official as saying.
In Washington, the FBI said it was cooperating with Saudi officials. "Our legal attache in Riyadh is working in concert with the Saudi officials and the State Department, and we can confirm he is in custody," said FBI spokeswoman Debbie Weierman.
On Saturday, al-Rasheed's father said his son had surrendered voluntarily to the Interior Ministry on Thursday in his hometown of Riyadh.
The ministry official said al-Rasheed has been in custody since Thursday, but did not say if he surrendered or was detained.
Initial investigations had shown al-Rasheed traveled to Afghanistan in June 2000 and returned to Saudi Arabia the following June, but that he had never traveled to America, the agency report said without elaborating further.
Al-Rasheed's father said Saturday his son was innocent of any connections to terrorists and had turned himself in after learning of the FBI's worldwide alert for his arrest, issue Tuesday.
The FBI bulletin said al-Rasheed was suspected of being "associated with the September 11, 2001 hijackers" and warned that he should be considered armed and dangerous.
The alert was issued after an image of al-Rasheed's Saudi passport was found among material "previously recovered during the war on terrorism" connected to the Sept. 11 hijackers.
America has blamed the Pentagon and World Trade Center attacks on al-Qaeda, the terror group led by Saudi exile Osama bin Laden.