"She looked like she was falling over, larking about like a child would," he said.
When he came closer, he could see that something was wrong. The girl - now identified as the al-Hillis' 7-year-old daughter, Zaina - was covered in blood and had "obvious head injuries." Zaina survived but was badly hurt while her 4-year-old sister Zeena was left unharmed.
At first, he said, he thought there had been an accident. But the dead French cyclist nearby was in a strange position and the punctures in the car's crumpled window appeared to be bullet holes. When he approached the car, it was clear the family had been shot to death.
"If you've seen CSI Miami, it was pretty much what you'd imagine a set from 'CSI Miami' to be like," he told the BBC. "There was a lot of blood and heads with bullet holes in them."
Martin said he had no idea - "none at all" - that there was another person in the car. The 4-year-old Zeena would lie undiscovered inside the car for another eight hours - apparently too shocked or scared to move.
Zeena is now with relatives in Britain and, Zaina is still recovering from her injuries in a French hospital.
Martin's U.K. telephone number was unlisted and few other contact details could immediately be located.