Defense Secretary Donald Rumsfeld alluded to the problem last month, telling reporters there had been “a mistake in one case” and that a detainee let go last year “has gone back to being a terrorist.” But administration officials tell NEWSWEEK that military intelligence has identified at least three additional “revolving door” cases of Gitmo detainees’ returning to the battlefield. One released prisoner, Mullah Shehzada, is serving as a “senior” Taliban commander. The officials say that alarming development–as well as information developed about four released detainees sent back to Britain–shows that the Gitmo population is far more dangerous than most of the public understands. Administration officials are especially aghast over the released British prisoners, who U.S. intelligence says are hardened Islamic extremists trained in urban warfare and assassination techniques at Qaeda camps before 9/11; one of them met several times with Osama bin Laden. “Rumsfeld has really been flagging this one hard in interagency meetings–that we need to be careful about who gets released,” says one senior administration official.

So why were they let out? A Pentagon spokesman says the screening process at Gitmo “is as stringent and thorough as possible, but it’s not foolproof,” adding that some of the prisoners were well versed “in counterinterrogation techniques and deception.” The spokesman refused to say whether authorities at Gitmo have tightened up their procedures. Other sources tell NEWSWEEK that the British prisoners fit into a different category: they were released because of intense pressure from a British government worried about a political backlash over the holding of British citizens in a U.S. detention facility.

In any case, the continued flap over Gitmo could strengthen the Justice Department’s argument to have a few prisoners transferred to the United States, where they could be tried in civilian courts. As rough as the Supremes were about Gitmo prisoners, Justice lawyers are bracing for an even rockier time this week when they try to defend the handling of two U.S. citizens, Yaser Hamdi and Jose Padilla, detained indefinitely by the U.S. military.