An RAF cyclist said that he came across the horrific French Alps killings to find a little girl "stumbling" around, bleeding and "moaning", it has emerged today.
Brett Martin said he initially believed there had been a terrible accident as he surveyed the scene in the secluded car park close to Lake Annecy.
The BMW's engine was still revving and its wheels were spinning, he told the BBC. Inside were the bodies of engineer Saad al-Hilli, 50, his dentist wife Iqbal, 47, and her mother.
A fourth body, that of Sylvain Mollier, 45, the French cyclist who apparently stumbled across the attack, lay on the ground.
Close by, Zainab al-Hilli, seven, was “prone on the road, moaning, sort of semi-conscious”, Mr Martin said.
The carnage resembled a Hollywood scene, he said.
“It was pretty much what you would imagine a set from (TV crime series) CSI Miami would be like,” he added.
“There was a lot of blood and heads with bullet holes in them.”
Mr Martin said he set out, as he had on most days that week, for a bike ride from his base at about 2.30pm.
But as he climbed to the top of a hill in the Combe d’Ire forest, near Chevaline, last Wednesday, he was faced with a bloodbath.
“It was the sort of thing you would never in your life expect to come across,” he said.
“As I approached the scene, the first thing I saw was a bike on its side. I had seen the cyclist ahead of me much earlier so I thought he was just having a rest.
“As I got a little bit closer, a very young child stumbled out onto the road and at first I thought she was actually just playing with her sibling because she sort of looked, from a distance, as if she was falling over, larking about like a child would.
“However, as I approached her it was obvious that she was quite badly injured and there was a lot of blood on her.
“As I got even closer, I then saw the car with its engine revving and its wheels spinning. It seemed at that moment in time like there had been a terrible car accident.”
At the time there was no sign of the al-Hilli's younger daughter Zeena, four, who had been cowering underneath her mother's body during the brutal attack.
Mr Martin said he immediately turned his attention to Zainab, first moving her body from where it lay in front of the car, fearing the vehicle could lurch forward and crush the child.
The little girl appeared “severely injured” and there was “a lot of blood”, he said.
He placed her in the recovery position and a few minutes later, she fell unconscious.
Turning to the BMW, he swiftly realised there was nothing he could do for its occupants.
“The thing that struck me was their complete inanimate nature, which was how I assessed really, without breaking into the car and physically handling them, that they were dead,” he recalled.
His RAF training meant he was able to keep a clear mind and “take stock” of the situation before deciding on how to proceed, he said.
Mr Martin, who switched off the car’s engine, said he then wanted to phone for help but found he had no reception on his mobile.
He realised he would have to leave the scene to make the call but this left him with the “dilemma” of whether to take young Zainab with him, or leave her where she lay.
Fearing that he could do more damage – and possibly kill her – if he lifted her, he set off on his bike.
“The wasn’t a very comfortable decision to have to make,” he said.
Meanwhile, the chief prosecutor in the area said that the causes and origins of the deaths lay in the UK.
Annecy's chief prosecutor Eric Maillaud made the comments as he travelled to the UK as investigators continue to probe the mystery.
Mr Maillaud and examining magistrate Michel Mollin, another senior member of the inquiry team, met officers from Surrey Police at Woking police station to discuss the case.
Yesterday the families of the deceased released a statement in which they said they were "heartbroken" by the deaths.
Mr Maillaud told reporters outside Woking police station it was "without any doubt that the reasons and causes have their origins in this country".
He added: "It is only by being together that we will find the murderers."
He thanked English authorities for their help with the inquiry.
Assistant Chief Constable Rob Price, who is leading the Surrey Police team, met the dignitaries.
He said: "As I stated previously, this is a French-led investigation. Surrey Police and other agencies within Surrey will do all we can to support this investigation.
"Inevitably, when you have different jurisdictions, there will be complexities and challenges.
"What I am please to report is that we have overcome these challenges and we are all determined to overcome future challenges.
"We are all operating with a determination and a focus and always have in mind the victims and all those who have been affected by this tragic incident."
The French officials have joined a small number of French investigators already in Britain to help unravel the mystery surrounding the deaths of the three Britons along with that of French cyclist Sylvain Mollier, 45, who apparently stumbled across the attack.
Mr Maillaud said yesterday that 40 French police officers were working on the complex case, which has led to a flurry of theories relating to possible motives.
He said investigators are focusing on three specific areas - Mr al-Hilli's work, his family and his native Iraq - as they try to find a motive for the murders.
Mr Maillaud is expected to visit the al-Hilli family home in Claygate, Surrey, this afternoon as part of his 24-hour trip to the UK and will also meet police officers and Crown Prosecution Service officials.
Yesterday's statement said the families had been "touched by the expressions of sympathy from people all over the world".
"We are very grateful for the support provided by the British, French and Iraqi authorities during this difficult time.
"We hope that those responsible for the deaths of our loved ones are brought swiftly to justice," it added.
Mr Maillaud said a number of witnesses have come forward in Annecy.
They include a hiker, named only as Philippe D, 41, who likened the carnage to a horrific film scene.
The walker described arriving at the site of the massacre, in the Combe d'Ire forest, near Chevaline, minutes after the attack at around 4pm last Wednesday.
There, in a small car park, he found the bodies of Mr and Mrs al-Hilli and her mother, named in reports as Suhaila al-Allafin, in their bullet-ridden BMW.
A fourth body, that of Mr Mollier, lay nearby and Zainab was found close by.
Sources said the victims were likely to have been shot with the same gun, fuelling speculation they were targeted by a contract killer. Each person was shot twice in the head.
Detailed ballistic analysis of 25 spent cartridges found at the scene suggests they all came from a 7.65mm automatic pistol.
The gun has been described as an old-fashioned weapon but one that is still sometimes used by special forces.
The victims' bodies have been returned to their families.