Defendant Salim Hamdan sits during his trial inside the war crimes courthouse at Camp Justice in this sketch 

REUTERS

A U.S. appeals court on Tuesday overturned the conviction of Osama bin Laden's former driver and bodyguard, Salim Hamdan, on charges of supporting terrorism, in a long-running case emerging from the American military trials at Guantanamo Bay, Cuba.

The U.S. Court of Appeals for the District of Columbia Circuit concluded that providing support for terrorism was not a war crime at the time of Hamdan's alleged conduct from 1996 to 2001 and therefore could not support a conviction, reports Reuters.

Human rights activists hailed the ruling as a blow to the legitimacy of the U.S. military commission system.

Hamdan was captured at a roadblock in Afghanistan in November 2001, not long after the U.S. invasion of that country following the September 11 attacks on the United States.

In the first U.S. war crimes trial since World War Two, Hamdan was convicted in August 2008 of providing personal services in support of terrorism by driving and guarding bin Laden, the al Qaeda leader who was killed in a U.S. raid in Pakistan last year.

Hamdan was sentenced to 66 months in prison but given credit for time served at the U.S. detention facility at Guantanamo Bay. He was returned to Yemen in November 2008 and set free in January 2009 to live with his family in Sanaa.

The appeals court found that even though Hamdan already had been released from U.S. custody, the appeal of his conviction was not moot.

At the trial, prosecutors said Hamdan was close to al Qaeda's inner circle while his lawyers asserted that Hamdan was simply a driver and mechanic in the motor pool who needed the $200 monthly salary.

Hamdan won a prior victory in 2006 when the U.S. Supreme Court scrapped the first version of the Guantanamo court system.