A 21-year-old Canadian terrorist suspect detained at Guantanamo Bay has been declared eligible to face trial by a U.S. Military Commission. He's the last Western citizen held at Guantanamo.

Lawyers, human rights observers and military officials were all present when the hearing of Omar Khadr, a 21-year-old Canadian citizen and terrorist suspect detained at Guantanamo, commenced.

However, an announcement by the defence looks likely to change the odds at the upcoming trial.

“There is a lot more going on behind the scenes,” stated Deputy Chief Defence Counsel Michael Berrigan, “The defence was not provided with potentially exculpatory evidence on the issue”.

Meanwhile his colleague on the defence team William Kuebler claimed that there would be new evidence presented.

Referring to the evidence he said, “It's an eye-witness the government has always known about. I'm going to say that the eye-witness is a U.S. Government employee and I'm going to say nothing more.”

Human rights observers say Khadr’s case could legitimise a system they perceive as unfair. They see it as a system that could unjustly convict many more detainees held by the U.S. government.

The U.S. government has twice attempted to try Khadr, who is accused of killing a US commando in Afghanistan and has been held in prison for more than five years.

Khadr was detained in Afghanistan in 2002 at the age of 15, following a shootout that left one American soldier dead and another injured. Khadr was charged with murder, attempted murder, planting bombs, spying for Al Qaeda and conspiring with Osama Bin Laden.

In June, a military judge, Peter Brownback, dismissed all charges. The case was not in his jurisdiction because Khadr had not been designated as an unlawful enemy combatant as required.

But an appeal's court decision has brought the case back to Guantanamo Bay, and this time the judge has changed his mind.

Whatever the outcome of this case, it is likely to be no-win situation for Khadr. He is likely to face many more years in jail.