The government of Malaysia made a curious announcement this week: Yazid Sufaat, a known al Qaeda operative, and four other alleged terrorists have been released from jail. It is not clear why Malaysian authorities thought it was time to set them free. Malaysia's home minister, Syed Hamid Albar, simply declared, "They are no longer a threat but they will be watched closely."

We can only hope.

Sufaat's newfound freedom is troubling. According to the 9-11 Commission, four top al Qaeda operatives stayed at Sufaat's apartment in Malaysia in January of 2000. The al Qaeda terrorists were in Malaysia for an important planning meeting, during which they discussed the upcoming attack on the USS Cole and details of the 9/11 operation. Shortly after the meeting, al Qaeda terrorists Khalid al Mihdhar and Nawaf al Hazmi, both of whom stayed at Sufaat's apartment, left for California. Twenty months later, al Mihdhar and al Hazmi were part of the team responsible for hijacking American Airlines Flight 77 and crashing it into the Pentagon.

Al Mihdhar and al Hazmi were not the only 9/11 plotters to receive Sufaat's hospitality. In the fall of 2000, Sufaat played host to convicted al Qaeda terrorist Zacarias Moussaoui during his visit to Malaysia. Moussaoui was scheduled to take part in the September 11 attacks, or a similar follow-on plot, but was detained by the FBI in August of 2001.

Thus, Sufaat assisted al Qaeda members during a crucial juncture in their operational planning for the 9/11 attacks.

At some point, a top al Qaeda operative named Hambali, who is currently a high-value detainee being held at Guantánamo, introduced Sufaat to al Qaeda's number two, Ayman al Zawahiri. Zawahiri wanted to jumpstart al Qaeda's program for developing anthrax and asked Hambali for assistance in finding a suitable scientist. Sufaat fit the bill. In 1987, he graduated from California State University at Sacramento with a bachelor's degree in biological sciences and a minor in chemistry. In 2001, Sufaat put his degree to work for al Qaeda. The 9/11 Commission found that he spent "several months attempting to cultivate anthrax for al Qaeda in a laboratory he helped set up near the Kandahar airport," which was then a stronghold for Osama bin Laden.

It was for good reasons, then, that Malaysian authorities detained Sufaat in December 2001. And there are good reasons to worry now that he has been freed. We must now rely upon the Malaysian government to make sure the freed Sufaat does not find his way back into al Qaeda's ranks.

Sufaat's story is not entirely unique, however. The U.S. government is relying on dozens of foreign governments to monitor both known and suspected terrorists who were once detained. For instance, the United States has transferred or released approximately 550 suspects from Guantánamo. While surely some of these men were innocents wrongly swept up in the fog of war, many of them were in fact part of the global terror network. In fact, some of them are well-acquainted with Sufaat's attempts to develop anthrax for al Qaeda.