The so-called 20th hijacker of the September 11 attacks has claimed members of the Saudi royal family directly supported the Al-Qaeda plotters.
Zacarias Moussaoui made the statements in testimony filed in Manhattan federal court by lawyers for attack victims who accuse Saudi Arabia in a suit of providing material support to Al-Qaeda.
But the Embassy of Saudi Arabia in Washington said in a statement on February 4 that Moussaoui's claims come from a "deranged criminal" and there is no evidence to support them.
Saudi Arabia said results of the most investigated crime in history show no involvement by the Saudi government or officials.
Moussaoui, a 46-year-old French native, pleaded guilty to terrorism charges in 2005.
He is serving a life sentence in a super-maximum security jail in the state of Colorado.