Doussari was among 16 Saudi prisoners inside the notorious US camp who arrived on Monday in Riyadh after being handed over to the Saudi authorities, Bahraini MP Mohammed Khaled said.
"Now we only have one Bahraini detainee, Issa al-Morbati," added Khaled, who also heads an non-governmental group that lobbies to free Bahraini prisoners in Guantanamo.
Six Bahrainis have been detained there. Three were released in November 2005 and a fourth was freed in October last year.
The Saudi interior ministry said on Monday that 53 Saudi inmates remained in the US detention facility and that 77 others have so far been handed over to Saudi authorities.
The controversial camp was established after the September 11, 2001 attacks on the United States to house prisoners captured in Afghanistan and elsewhere.
Some 800 detainees have passed through the camp since it opened, and several hundred are still held there.
Passports for bedoons in Kuwait
