The Taleban leader who killed himself to avoid capture by Pakistani security forces Tuesday was released from the U.S. detention center at Guantanamo Bay three years ago.  Pentagon officials say they do their best not to release detainees who will return to terrorism, but this Taleban operative was not the only one to do so.  VOA's Al Pessin reports from the Pentagon.

Abdullah Mehsud, a former Guantanamo Bay prisoner, talks to the media as his bodyguard stand guard near Chagmalai in South Waziristan along the Afghan border (2004 file photo)

Mehsud was a Taleban fighter in the 1990s, and he lost a leg in a land mine explosion shortly before the Taleban took Kabul in 1996.  In 2001, during fighting against the Northern Alliance, he was taken prisoner.  He was transferred to U.S. custody after the U.S.-led invasion of Afghanistan, and he was sent to the Guantanamo detention center shortly after it was established.

During 25 months there, he managed to conceal his identity and convinced his interrogators he was an innocent man caught up in the fighting.  He was released in March of 2004.  Just a few months later, Mehsud masterminded the kidnapping of two Chinese engineers in Pakistan's tribal areas.  One of them was killed during a rescue attempt.  Since then, he is reported to have become a leader of Taleban cells in the rugged mountains of western Pakistan.

On Tuesday, according to Pakistani officials, when a team of their intelligence agents surrounded the house where Mehsud was hiding in Baluchistan Province, the prominent Taleban fighter killed himself with a hand grenade.

Pentagon Spokesman Bryan Whitman says it is not easy to determine who to hold at Guantanamo and who to release.

"We have to make judgments and decisions about who to continue to detain and who to release.  And it's not a perfect system," Whitman said.

That system has been widely criticized by human rights groups, which say the Guantanamo detainees should either be tried or released.  But the Defense Department says much of the evidence against the detainees is classified, making public trials impossible.  Instead, it has an annual review process to determine, in secret proceedings held by military officers, whether each detainee is still a threat to U.S. security.

"It is a rigorous process.  And while it is a rigorous process, it's not a perfect process," Whitman said. "And we know we have released individuals that have returned to the battlefield."

Mehsud was released before the current review process was established.

In addition, the Bush administration is trying to hold military tribunals for some of the detainees, which could result in formal sentences.  At least parts of the process are open to the public.  But the plan has run into a series of legal challenges.  And Defense Secretary Robert Gates has said that, because of the nature of the evidence, there are some detainees at Guantanamo who cannot be released or tried.  It is not clear what will happen to those men in the long term.