Five percent of inmates released from the Guantanamo Bay US lockup have participated in terror since their release from the US Navy prison, the US Defense Department said Tuesday. An additional 9 percent are believed to have joined or rejoined the fight against the United States and its allies, according to Pentagon data released amid a simmering political battle over where to send the detainees if the prison should close in January as planned. Constitutional scholars have long cast doubt on the Pentagon's detainee data, saying it is not proved that at least some of those who were released were even linked to terrorism in the first place. The Pentagon maintains that all the Guantanamo detainees were captured and, in most cases, held for years without formal charges, because of suspected ties to al-Qaida, the Taliban or other foreign fighter groups. "What this tells us is, at the end of the day, there are individuals, that if released, will again return to terrorist activities," Pentagon spokesman Bryan Whitman said Tuesday. As of April 7, the latest data available, 74 of approximately 540 detainees that have been released have since taken up the fight, or are at least suspected of doing so. The Pentagon says it has fingerprints, DNA, photos or reliable intelligence to link 27 detainees to the war since their release. Speaking out against the United States, or participating in other anti-US propaganda alone is not considered terrorist activity, the Pentagon said.