James Foley and 3 other journalists last seen being taken by Gaddafi forces.
Turkish officials said four foreign journalists are expected in Tripoli today.
At least 3 captured journalists spotted inside a Tripoli detention center.
Al-Jazeera journalist released; four Western journalists still missing.
James Foley, along with 3 other foreign reporters, were taken by Gaddafi forces.
Human rights group calls on Gaddafi to free James Foley and other reporters.
Correspondent James Foley called home in first contact since being detained.
A recent visit confirms they are in good health, but concerns remain.
4 reporters, including 2 Americans, have now been held in Tripoli for six weeks.
South African photographer also said to be safe in Libya.
Journalist James Foley reporting for GlobalPost from Benghazi, Libya in mid-March. Foley, along with three other foreign journalists, was detained by forces loyal to Libyan leader Muammar Gaddafi on April 5.