The suspected mastermind of the Sept. 11 attacks is cooperating with his defense _ an apparent break with other Guantanamo prisoners who are boycotting their war-crimes trials.

Khalid Sheikh Mohammed’s Pentagon-appointed attorney, Navy Capt. Prescott Prince, says that he plans to meet Mohammed Thursday for a second time at the U.S. Navy base in Guantanamo, Cuba. Military secrecy rules prevent Prince from discussing what transpired during the first meeting.

Prince said Tuesday that delays in security clearances for two civilian attorneys have stalled their preparation for the death-penalty case.

Mohammed is expected to be arraigned in June before a U.S. war-crimes court along with four other alleged Sept. 11 conspirators.