Two UK security consultants and the contractors they were guarding were killed in an ambush by a suicide bomber in Iraq, an inquest has heard.
The victims were leaving Baghdad Airport when they were killed
The four workers died when their armoured land cruiser was blown 70ft off a flyover by the blast in 2004.
John Dolman, from Belfast, Nicholas Pears, from Hemel Hempstead, John Eardley, from Glasgow, and American Tracy Hushin were killed instantly.
Oxford Coroners' Court recorded a verdict of unlawful killing.
Oxfordshire assistant deputy coroner, Selena Lynch, said she "despaired" of such cases in which others were "prepared to sacrifice their own lives in order to take the lives of others".
The inquest was told how the four victims were trying to reach the safety of the city's green zone when they were killed in January 2004.
They were driving from Baghdad airport on a road which had been targeted several times by insurgents intent on killing foreign contractors.
Mr Dolman and Mr Pears, both of risk consultant company Kroll Group, travelled in convoy with Mr Eardley and Miss Hushin in the front car, followed by back-up personnel in other vehicles.
Miss Hushin, 34, was an employee of US consulting firm Bearing Point and Mr Eardley, 56, was working for IPA Energy and Water Consulting.
One of the drivers in that convoy, Pat Tynan, gave evidence at the inquest.
He described the moment he saw a red Vauxhall car that had been travelling just ahead of the group indicate as if to turn through a gap in the central reservation to make a U-turn.
"We saw that sort of thing happening every day in Iraq. It was part of normal traffic," Mr Tynan said.
But moments later the vehicle exploded, catapulting team leader and former paratrooper Mr Dolman's vehicle off the road.
"Insurgents would have had prior knowledge that an inbound flight was coming in from Jordan," Mr Tynan said.
"They knew that they had a window of time when travellers were coming from the airport to the green zone. We tried to frustrate that as much as we could by varying the time that we left the airport."
The court heard that Kroll had scaled down its work in Baghdad by the time of the attack.
It had only two teams compared to an earlier 20 and the coroner was told the company kept a low profile to ensure the safety of those being protected.