MIAMI — A 37-year old Afghan detainee died at Guantanamo Bay in an apparent suicide, the US military said in a statement.

The man, identified by one name, Inayatullah, was an admitted planner for Al-Qaeda terrorist operations, according to the Southern Command. He arrived in Guantanamo in September 2007.

Inayatullah was the eighth person to die at Guantanamo since the US government started transferring prisoners there following the 2001 ouster of the Taliban in Afghanistan.

According to the statement, Guantanamo guards found the detainee unresponsive and not breathing during a routine check Wednesday. "After extensive lifesaving measures had been exhausted, the detainee was pronounced dead by a physician," the Southern Command said.

It added that Inayatullah had met with local operatives, developed travel routes and coordinated documentation, accommodation and vehicles for smuggling Al-Qaeda fighters through Afghanistan, Iran, Pakistan and Iraq.

The Southern Command said the Naval Criminal Investigative Service will investigate the incident, something it does with all detainee deaths.

Last year, a US federal judge dismissed a complaint by the families of two Guantanamo detainees who claimed their deaths in 2006 had been covered up when the Pentagon ruled them suicides.

The Pentagon had maintained that the two men, Saudi prisoner Yasser al-Zahrani and Salah al-Salami of Yemen, along with a third detainee, Mani al-Utaybi of Saudi Arabia, committed suicide by hanging themselves in their cells. Utaybi's family did not file a complaint.