What went wrong in the French Alps murder investigation – by the detective who saw it all

·12 min read
September 2012: The scene of the crime, one of the most staggeringly violent murder cases of our age - Julian Simmonds
September 2012: The scene of the crime, one of the most staggeringly violent murder cases of our age - Julian Simmonds

There are images Mark Preston wishes he could erase from memory, but after a 30-year career as a detective, a handful of cases invade his thoughts on an almost daily basis. One is the unsolved, staggeringly violent case of the al-Hilli family, three of whom were, along with a French cyclist, shot dead in an Alpine beauty spot on 5 September 2012.

A decade on, Preston, who led the British end of the investigation for three years, can still see the crime-scene photos of Saad al-Hilli, his wife Iqbal and her mother Suhaila al-Allaf, each shot twice in the head, in the family’s bullet-riddled BMW. He thinks about the two little daughters who somehow survived the attack, and wonders what their lives are like today. He goes over and over the facts involuntarily, wondering what he could have done differently and what he might have missed.

‘It leaves an emotional footprint,’ he says.

Having worked on dozens of murders, the al-Hilli case is the retired detective chief inspector’s major unfinished business. It is also the ‘most complex and challenging’ investigation of his career – but it should not have been unsolvable.

Preston believes the murder inquiry was hampered by a series of blunders by French investigators, who apparently failed to secure vital pieces of evidence and, in his view, spent years going down blind alleys. He claims that instead of keeping an open mind about who might have pulled the trigger, and why, they fixated on a single theory, eventually abandoned, meaning the trail had gone cold by the time they considered alternatives.

‘The French were incompetent ... The investigation was damaged by egos,' says Mark Preston, retired DCI - Aloha Bonser-shaw
‘The French were incompetent ... The investigation was damaged by egos,' says Mark Preston, retired DCI - Aloha Bonser-shaw

‘I couldn’t get the investigation in France to change direction and that I bitterly regret,’ he says. ‘There were times when the French asked us to do things and we took them at face value because we were fearful of damaging the relationship, when we should have just said, “You’re wrong.”’

This is all laid out in a new three-part Channel 4 documentary, Murder in the Alps. Preston, who retired from Surrey Police in 2019, hopes it might persuade someone to come forward with some information that could unlock the case. ‘There could be someone who was in a relationship with the gunman who is willing to come forward, or someone decides they can’t live with the guilt any more, or it could be a serving prisoner who said something to someone,’ he says.

As to his belief about what happened: ‘When I combine all the evidence, there is one theory that would stand up to scrutiny, that fits very nicely…’

The case became an international news story, not least because it made so little sense. Why would anyone have gunned down a middle-class British family, on a last-minute caravanning holiday to France, as they took an unplanned drive up a mountain road near Lake Annecy?

Saad al-Hilli had stopped the family car in a lay-by and his eldest daughter, Zainab, then aged seven, had got out with him to look at a sign showing hiking trails. Before the rest of the family could get out of the car, the killer was upon them, firing at least 21 shots from a pre-Second World War Luger pistol. Saad managed to get back in the car, shouting to Zainab to do the same, and tried to drive away, only for the car’s wheels to get stuck.

The gunman ruthlessly picked off Saad, 50, Iqbal, 47, and Suhaila, 74, as well as local cyclist Sylvain Mollier, 45, who had stopped to attend to his bike chain. Zainab was shot in the shoulder as she tried to get back in the car, and pistol-whipped over the head. She narrowly survived after being put into a coma for days. Her sister Zeena, aged four, ducked into the rear passenger footwell when the shooting began and hid under her mother’s legs. Eight hours later she was found, physically unharmed and still hiding, by French police.

This is the first in a series of questions levelled at French police in the documentary: why did it take eight hours to find her?

The investigation was already eight months old when Preston joined it, taking over from the previous senior investigating officer, who was moving on to another role, and he had concerns of his own: ‘My first impression was that the investigation had grown too big. There were lines of investigation that were taking up extraordinary amounts of time that were unnecessary,’ he recalls.

‘There was a big gap between my expectations and what was delivered by the French. From a forensics point of view, the crime scene was carnage. Items that were found in one part of the BMW were moved to another part… There was incompetence on the part of the French. But the bigger mistakes were strategic.’

In overall charge was Eric Maillaud, the local prosecutor who had announced a week after the murders that ‘the reasons and causes have their origins in [the UK]’. The more Maillaud dug into the al-Hillis’ background, the more convinced he seemed to become that secrets within the family held the key.

Saad had fallen out with his brother Zaid over inheritance, and there were unproven allegations of a forged will. There was a Swiss bank account with almost a million euros in it that had belonged to their late father. Saad had a Taser in his home; police concluded he may have been worried about his safety. Zaid was arrested and questioned by Preston as part of the investigation.

Saad al-Hilli’s impromptu holiday ended in tragedy - Enterprise news and pictures
Saad al-Hilli’s impromptu holiday ended in tragedy - Enterprise news and pictures

But the police’s job is to prove who committed a crime, and how, not why. Zaid had been in England at the time of the murders and, after months of ‘overt and covert’ evidence-gathering, there was ‘not a shred of evidence’, says Preston, that he was involved. Preston is convinced of his innocence.

Investigators also made inquiries in Iraq, chasing down rumours that the al-Hillis, who came to the UK in 1968, had connections to Saddam Hussein. It went nowhere. There were reports that Saad, who worked for a company that makes satellites, could have been a spy, killed as part of an elaborate plot after arranging to hand over secrets. That, eventually, was also ruled out.

Maillaud also discovered that Iqbal al-Hilli had lived in Louisiana before she met Saad, where she married a local man in 1999 and for 18 months was known as Kelly Thompson. Astonishingly, it emerged that her former husband, James Thompson, had died on the day of the murders. Was Iqbal the real target? The French wanted to exhume James’s body to see if he had been poisoned (rather than had the heart attack that was given as his cause of death) but US authorities declined.

Maillaud’s belief that the al-Hillis had been the victims of a contract killing was heightened by another mystery: Saad and Iqbal’s passports were missing. Had they been taken by a hitman as proof that he had got the right targets? No. Almost two years after the murders, Saad’s passport was found in the pocket of his jacket, which had been bagged up without being properly searched.

It was another terrible oversight by the French investigators – and there were more. The most important witness was a British RAF veteran called Brett Martin, who had been passed by Mollier as they both cycled up the hill; he was the first to discover the bodies and put Zainab in the recovery position. His clothes were covered in blood and he had touched a victim who had been in close contact with the killer, but the police did not immediately seize those clothes for forensic analysis – after he returned home, they were washed.

Gendarmes attend the campsite where the al-Hilli family were staying - Alamy Images
Gendarmes attend the campsite where the al-Hilli family were staying - Alamy Images

Preston believes the French authorities’ insistence that the al-Hillis were the target of a ‘hit’ led to a blinkered ‘groupthink’ approach that ignored contradictory evidence and failed to explore other possibilities. ‘My experience is that investigations can often be damaged by egos,’ he says, ‘and I don’t think this case was any different.’

Could investigators have been too eager to prove that foreign victims had been preyed on by foreign criminals, rather than having to look for evil in their own midst? ‘Hugely so,’ Preston says. ‘Within days of the inquiry starting, they were saying the answer lies in the UK. That’s an incredibly bold statement to make at a time when they couldn’t possibly be sure, and having made that statement, human nature makes it difficult to go back on it and admit you were wrong.’

From the outset, Preston harboured an alternative theory. What if the al-Hillis were not the targets? In that case, everything about their colourful backgrounds would be a red herring. ‘I began to have my doubts that the al-Hillis were the target the first time I drove up the road to the murder scene,’ he says. ‘It’s a couple of miles of single-track road, so following someone up there is unlikely.’

No one apart from the al-Hillis knew where they were going that day, so the idea of a gunman lying in wait for them seems impossible. If the family were the targets, why did the gunman, who tried to kill Zainab, apparently have no idea they had another daughter? And why would a professional hitman use such an antiquated weapon?

The family were caravanning beside Lake Annecy - Julian Simmonds
The family were caravanning beside Lake Annecy - Julian Simmonds

Ballistics reports revealed another disturbing fact: Mollier had been shot no fewer than seven times, more than any other victim. When Preston reconstructed the sequence of events, he became convinced that Mollier was shot first, and that after turning his gun on the al-Hillis, the killer went back and shot Mollier again, in the face. Had Mollier been the intended target all along?

‘To me it was very clear the killer wanted Mollier dead,’ says Preston. It is this theory that ‘fits nicely’ with the circumstances, he says.

Mollier, a divorced factory worker, had started a relationship with Claire Schutz, a local whose family owned a lucrative pharmacy business and who had recently given birth to his child. Mollier was known to go cycling in the area, and may well have mentioned to someone where he was going that day.

The car park marked the end of the metalled section of the road and he was on a road bike, so it was a logical place to predict he would take a break or at least turn around, and the obvious place to pick him off. The use of a Luger also points to a local killer; they were issued to Swiss soldiers for decades and many remain in circulation in the area, close to the Swiss border.

‘Maybe the gunman struck lucky by having the al-Hillis there,’ suggests Preston. ‘By killing the al-Hillis, it would have helped to disguise the real target and made the investigation much harder.’

If that is the truth, it seems to have worked.

French prosecutors are now working on the theory that it was a random attack. Preston shakes his head: ‘I don’t think it was random.’

‘It makes me grateful for my family. I don’t take them for granted,' says Preston - Aloha Bonser-Shaw
‘It makes me grateful for my family. I don’t take them for granted,' says Preston - Aloha Bonser-Shaw

Maillaud says in the documentary that failing to find the passports for two years was ‘a mistake’, which was ‘down to the clumsiness of some of the investigators’. He dismisses as ‘fantasy’ the idea that influential people could have orchestrated a cover-up if Mollier was the intended target, and adds, ‘There are questions which we could ask for ever and I’m not sure we’ll ever get answers.’

Earlier this year, Annecy public prosecutor Line Bonnet told a Swiss newspaper: ‘I think we’re nearly there. We’ll succeed thanks to scientific evidence.’ Preston is mystified as to what this new scientific evidence might be, and says, ‘Without someone new coming forward, I don’t think it will be solved to the extent of prosecuting someone.’

Ten years on, Preston, now 52, works in the NHS as a manager and is a part-time leadership coach – but somehow he retains the aura of a hard-boiled murder cop. He admits that when he moved on from the major crime team in 2016, taking on a more managerial role and handing over the al-Hilli investigation, it was because he had had enough. ‘I reached a position where I had had my fill of the misery caused by murder,’ he says.

A father of four, he frequently catches himself imagining Saad al-Hilli’s desperate final moments – his own daughter was four at the time of the murders. ‘[Saad] got back in the car when he saw the gunman, but his daughter was still outside. He knows that if he doesn’t get out of that car park, he and the rest of his family will die, but one daughter is not in the car. Imagine that terror, that panic.’

Though he has left the force, Preston still struggles. ‘My experience was perhaps easier to deal with in the moment, when I was busy, than maybe it is retrospectively,’ he admits. ‘I dropped my daughter off this morning. And I know I may never see her again. That’s not meant to sound pessimistic, but it’s a fact. She could disappear. I could die.’

It is a bleak outlook, but, he says, ‘It makes me grateful for my family. I don’t take them for granted. So I want to make sure every goodbye I give to them is meaningful, not just a quick “bye”.’

Murder in the Alps starts on Channel 4 tomorrow, with all episodes available on All 4