Use of military contractors - and their legal accountability - have come to the forefront in Afghanistan and Iraq [EPA]

Jury selection is scheduled to begin in Virginia in the trial of two former defence contractors charged with the deaths of two Afghan nationals.

The trial of Justin Cannon of Corpus Christi, Texas, and Christopher Drotleff of Virginia Beach begins on Tuesday in US District Court in Norfolk. It's expected to last two to three weeks.

The former contractors for Blackwater Worldwide are accused in the shooting deaths of two Afghan nationals in Kabul in May 2009. Drotleff and Cannon have said they opened fire on a vehicle when it sped toward them.

Cannon and Drotleff were arrested by FBI agents in January, and face a 13-count indictment.

The defendants were in the country to train the Afghan National Army. Drotleff and Cannon face up to life in prison if convicted. North Carolina-based Blackwater is now known as Xe Services.

Drotleff served three years in the marines and left with an other-than-honourable discharge in 2001. His military record included offences for unauthorised absences, assault and falsely altering a military ID card. Cannon was discharged from the army after going AWOL and testing positive for cocaine. He later succeeded to have his military records officially changed to an honourable discharge.

But even before President Barack Obama announced the end of the US combat mission in Iraq, contractors outnumbered uniformed personnel.  

Previous cases

This is not the first time military contractors have faced criminal charges in the US.

Don Ayala, a former military contractor, pleaded guilty to manslaughter in 2008 after he shot and killed  handcuffed prisoner Abdul Salam in Afghanistan. Although the charge could carry a prison sentence of eight years, Ayala was given probation in 2009 due to what lead up to the shooting. 

The AP reported that Salam was talking to anthropologist Paula Loyd - who was there as part of a US Army project - in the village of Chehel Gazi when he suddenly doused her with gasoline and set her on fire.

When Ayala, who was Loyd's colleague, was told of her injuries, he shot Salam in the head.

In 2008, five Blackwater guards were charged for the deaths of 17 Iraqi civilians in 2007. The men said they were acting in self defence when they opened fire on crowded al-Nisoor Square in Baghdad, and in 2009, a US judge dismissed the charges against them, because, he said, the US department of justice had used inadmissible evidence against the men.