The massacre in the Alps

Who - or what - was it that lured the al-Hilli family to their deaths in a remote French forest?

Wednesday afternoon was misty in the mountains above Lake Annecy. It was not a day for sunbathing, or swimming, at the campsites that cluster along the western shore of one of the most beautiful lakes in Europe.

Nor was it much of day for a walk in the mountains. Why did the al‑Hilli family leave its caravan at the campsite at Saint Jorioz and drive 10km to the village of Chevaline above the southern tip of the lake? Why did Saad al-Hilli drive his wine‑coloured BMW estate past the sign marked "dangerous road" and up the three winding, pot-holed kilometres of the "Route forestière de la Combe d'Ire"?

If they intended to go for a ramble, it was scarcely the day for it. All five people in the car – Mr al-Hilli, 50, his wife, Iqbal, 47, an elderly woman who may have been her mother, and the little girls, Zainab, seven, and Zeena, four, were dressed in what French investigators describe as "smart town clothes".

To understand what happened next – or to comprehend the depth of the mystery of what happened next – it helps to picture the spectacularly beautiful scene at the top of the Route de la Combe d'Iré. A red and white sign orders the public to drive no further. A typical Alpine forest climbs away steeply to the left. On the other side of the track, there is a near-vertical drop to a surging stream.

A parking area, no more than a lay-by with space for five or six cars, has been carved from the mountain side. It was in this spot, a place at once beautiful and banal, that a killer or killers – probably just one killer, according to a leak from the investigation yesterday – clinically slaughtered four people just before 4pm on Wednesday.

There is clear evidence, written into the mountainside by Mr al-Hilli's car, that he knew he was about to die. The BMW was reversed at speed into the near-vertical bank beside the parking area. Gouge marks, two feet up the embankment, were visible when the site was reopened to the press and public on Friday afternoon.

When a British cyclist stumbled on the massacre scene at 10 minutes to four, the engine of the car was still running. The doors were locked. The BMW was jammed hard against the mountainside. Mr al-Hilli did not have time to turn his car around before he was shot three times, including twice in the forehead, through the front window. His wife and the older woman were also shot three times each, including once in the head.

The gunman presumably did not notice Zeena, who had taken refuge under her mother's skirt. Nor did the first person who arrived on the scene, the British cyclist, an RAF veteran. And, incredibly, for the next eight hours, the local gendarmes failed to realise that there was a little girl lying unharmed but paralysed with terror below her dead mother's legs.

The British cyclist also discovered sprawled beside the car the body of another cyclist, Sylvain Mollier, 45, who had overtaken him on the winding climb to the parking area a few minutes earlier. Seconds before, the British cyclist had found wandering in a daze, before she collapsed at his feet, seven-year-old Zainab, who had been shot in the shoulder and repeatedly struck on the head.

His prompt action in placing her in the recovery position on her side and telephoning emergency services saved the little girl's life. She is recovering slowly after a series of operations at a hospital in Grenoble.

Zainab al-Hilli may be the only person who can clear up the mystery of what happened to her family – and why. Her younger sister can recall only screams, loud noises and her own terror. Two unnamed relatives and a British social worker arrived in France yesterday to take her back to Britain.

The working theory of French investigators is that there was something in Mr al-Hilli's past – or maybe in his present – that explains why his family was attacked in such a remote and unlikely place. Mr al-Hilli came to Britain from Iraq as a teenager in the 1970s, after his father fell out with the Ba'ath Party and his mechanical engineering business was impounded.

Mr al-Hilli became an engineer and started his own small aeronautics design business, Shtech Ltd, in 2001, running it from his detached house in Claygate, Surrey. Julian Stedman, his accountant, said the firm worked on projects including ones for the aircraft manufacturer Airbus, and that the company was doing well. Online records show that Mr al-Hilli was also a director of a Swindon-based company offering "business services, aerial photographers and surveys services". In addition, he had worked for Guildford-based Surrey Satellite Technology as a contract mechanical design engineer since November 2010. Reports that he was known to the security services and put under Special Branch surveillance during the second Gulf war have since been dismissed as inaccurate.

Much has been made of a report, emanating from British police according to the French prosecutor, that there was a dispute between Mr al-Hilli and his brother Zaid, apparently over the estate left by their father. However, on Friday, Zaid al-Hilli went to British police and told them: "I have no conflict with my brother." But Mae Faisal El-Wailly, a childhood friend of the brothers, made available a letter written to her by Saad al-Hilli last year that alluded to a possible inheritance dispute. She said the brothers' father had died recently, and she described the family as wealthy and well travelled.

The letter was dated 16 September 2011, and in it Saad al-Hilli wrote: "Zaid and I do not communicate any more as he is another control freak and tried a lot of underhanded things even when my father was alive. He tried to take control of father's assets and demanded control. Anyway it is a long story and now I have just had to wipe him out of my life. Sad but I need to concentrate now on my wife and two lovely girls..." Zaid al-Hilli has yet to give his response to this letter.

None of this, even if a family falling out were true, would account for the ferocity of last week's slaughter in the forest. French investigators believe that at least 25 shots were fired in a matter of seconds. There is a strong presumption that the automatic pistol, or pistols, were fitted with a silencer. The RAF veteran heard no shots in the quiet forest. He did see a green four-wheel-drive car and a small motorcycle descending the track from the massacre scene.

Everything points to "an ambush", the chief prosecutor for the Annecy area, Eric Maillaud, told a local newspaper on Friday – before retracting the word at a press conference. The three victims inside the BMW were carefully slaughtered from point-blank range with shots to the head and body.

And yet, French investigators point out, the behaviour of the gunman or men was not wholly that of a professional hitman. The French cyclist, believed to have been an innocent bystander, was shot five times. "That is not the behaviour of a professional," one French investigator said. "The killer appears to have been in a rage, perhaps because the cyclist tried to intervene."

There is also the mystery – a mystery within a mystery – of what happened to seven-year-old Zainab. How did she come to be wandering outside the locked car? Why was she shot in the shoulder and then beaten about the head, rather than finished off?

Officially, French investigators are keeping all options open: it might have been an attack by a deranged individual; an attempted robbery; it might even – although this is not taken seriously – a targeted attack on the local cyclist, Mr Mollier.

It is clear that the French investigators believe that the mystery will be solved in Britain, not France. Four senior gendarmerie detectives have arrived in Britain for what Mr Maillaud called a "Franco-British investigation". An international warrant has been issued in France which has allowed British police – in the presence of the gendarmes – to search the al-Hillis' house in Surrey and to question Mr al-Hilli's brother Zaid.

Many, many puzzles remain. Who was the woman aged 75 with Swedish and Iraqi passports who died in the back of the al-Hilli BMW? She is presumed to have been Mrs al-Hilli's mother but little Zeena has told investigators that she had scarcely ever met her.

Were the al-Hillis really planning to ramble in the mountains in the mist in their "smart, town clothes"? Or were they fleeing for their lives? The gouged earth high in the bank at the parking place is regarded as a key piece of evidence.

One theory being examined by French investigators is that Mr al-Hilli left the campsite because he felt threatened. He realised he was being followed. He tried to shake off his pursuer on small country roads. When he reached the sign ordering cars to stop, he tried to turn around in a panic. The killers, or killer, arrived before he could drive away.

But how did young Zainab come to be outside the car? That is something that only she, or the killer, can explain.

Echoes of an unsolved murder from the past

Sixty years ago, another British family was found slaughtered in and around its car in southern France. The murders have never been satisfactorily explained, not least because of suggestions of espionage, secret meetings and a confession of sorts by an apparent assassin.

It was near the village of Lurs, four hours' drive south of where last week's shootings occurred, that the bodies of Sir Jack Drummond, his wife, Ann, and daughter Elizabeth, aged 10, were found on 5 August 1952. The girl had been bludgeoned to death, her parents shot with an ex-US army rifle. A local farmer, Gaston Dominici, 75, made a drunken confession, withdrew it, but was convicted and sentenced to death. But so flawed was the case against him that his sentence was commuted, and then, in 1960, he was freed. He was not, however, exonerated.

What did – and still does – give the case its considerable spice was that Sir Jack had been a prominent government scientist. He was a nutritionist involved in the discovery of vitamins and the formulation of wartime diets who had, in the late 1940s, gone to work for Boots Ltd directing research into, among other things, fertilisers and weedkillers. And, not far from where he was killed, there was a factory making agrochemicals.

Sir Jack, it was learnt, had visited the area several times in previous years, and this, plus his government connections and a meeting just before his death with a prominent member of the wartime French Resistance, gave birth to several theories about his death. Some said he was in France not so much on holiday but to investigate the nearby factory. His camera, for example, was never found. Others feel he was trying to reclaim for the British government a large consignment of gold given to the Resistance.

And then there was the arrest in Germany and reported confession of a William Bartkowski, who said he was one of four men contracted to murder Sir Jack. The motive, presumably, was related to the Cold War, a not entirely implausible scenario that bears comparison to the way Iranian scientists have recently been regularly killed off.