Michael B. Mukasey, President Bush’s choice to replace outgoing Attorney General Alberto Gonzales, was the judge presiding over the terrorism trial of blind Sheikh Omar Abdel Rahman in 1995. The New York Times lauded Mukasey for sentencing the sheikh to life in prison; what’s less well known is that Mukasey let a top al Qaeda organizer who should have served as a witness in that trial off the hook, according to Peter Lance, author of Triple Cross: How bin Laden’s Master Spy Penetrated the CIA, the Green Berets, and the FBI.

The missing witness, Ali A. Mohamed, was a double agent, working for the FBI and al Qaeda at the same time but with a primary loyalty to al Qaeda. Mohamed set up al Qaeda training camps in the Sudan and brought bin Laden lieutenant Ayman al Zawahiri on a fundraising tour of American mosques in 1992. Remember how the Bush administration has scolded Canada for not doing more to stop terrorism? In 1993 the Mounties arrested Mohamed for trying to help an al Qaeda activist gain entry to the U.S., but the FBI got him released.

After that he went to Kenya and took photos of the U.S. embassy, photos believed to have been used to plan the bombings of that embassy in 1998. Later, while serving with the military at Fort Bragg, N.C., Mohamed stole intelligence documents, including secret memos from the Joint Chiefs of Staff.

Lance explains convincingly that the FBI didn’t want Mohamed at the blind sheikh’s trial because his testimony might have given away the fact that he was working as an FBI informant and planning terrorist actions simultaneously in the ‘90s. Then-Judge Mukasey refused to issue a bench warrant to force Mohamed to testify, or even to give the jury a so-called “missing witness charge,” which means telling the jury that a certain witness would not be called and allowing them to infer that that witness’ testimony would be damaging to the party (the federal government in this case) that could produce him, but refuses. That part of the process might have opened up information about Mohamed that government agencies could have shared, giving them a wider information base that might even have helped prevent the 9/11 attacks.