Families of mercenaries killed in Fallujah sue US security firm

It was just one of the grisly episodes in the war in Iraq. Four American mercenaries, sent to Fallujah in March 2004 to escort a convoy of empty trucks were overcome by an angry mob after they were shot in an ambush. They were burnt in their vehicles and the image of their charred bodies strung up from a bridge was among the most disturbing of the conflict.

But for the families, the torment has continued as they still do not know why their husbands - employees of Blackwater USA - were sent to the killing grounds of Fallujah without enough protection or firepower. They are suing Blackwater, alleging that the men should have had armoured vehicles and a rear gunner to protect them.

They is little public sympathy for the deceased, for whom money seems to have been the main motive for being in Iraq, but there is growing concern about the lack of oversight or control over the organisations that send the mercenaries into war zones, whether it is Iraq or Afghanistan.

As the US prepares to begin withdrawing its armed forces in Iraq, contractors such as Blackwater are moving centre stage, providing more and more of the core fighters deployed by the US, but with the advantage of deniability and lack of accountability when things go wrong. The kidnapping of five Britons from Iraq's Finance Ministry in Baghdad included four bodyguards employed by the Canadian security firm GardaWorld, another contractor that operates below the radar of direct military supervision.

There are some 50,000 mercenaries operating in Iraq. They escort convoys, train the Iraqi army and guard diplomats and interrogate prisoners. They operate in a legal twilight zone fostered by the Bush administration, while enabling US military to remain as slim as possible. But four years into the Iraq war, little is known about how they operate or what their rules of engagement are.

The US military has depended on private contractors since the American revolutionary wars. But today, the US has become dependant on armed mercenaries and it has done so without any formal oversight by Congress or even, it appears, the military.

Blackwater has countersued the families in the Fallujah incident for $10m, saying that they have violated contracts that forbid the men or their estates from suing the company. So far, Blackwater is winning in the courts and the families have been forced into arbitration.

The four men killed in Fallujah were all former members of the US special forces.