In the serene, sun-dappled Alpine forest, it is hard to imagine the sharp crack of pistol shots drowning out the gentle sound of the gurgling river below.

For hikers and cyclists heading up the mountain footpaths beyond, the Le Martinet parking layby above Lake Annecy is a place of tranquility.

But for British accountant Zaid al-Hilli, who is visiting this sublime spot for the first time, its natural beauty cannot cancel out the cold-blooded attack that happened right here, in which his brother Saad was one of four victims shot dead at point-blank range.

Standing on the exact spot where the body of Saad was found at the wheel of his bullet-ridden BMW estate, Zaid, 67, pauses in quiet contemplation, trying to imagine the horror that unfolded and changed his life for ever.

It is 14 years since a gunman killed Saad, 50, of Claygate, Surrey, his wife Iqbal, 47, her mother Suhaila-al-Allaf, 74, and local cyclist Sylvain Mollier, 45.

This week, having been afraid for so long to go to the place where his beloved brother died, Zaid finally made the sombre pilgrimage.

‘It feels very strange being here,’ he admits. ‘You can hear the river, and I can imagine Saad would have appreciated that. I understand why he would have got out of the car and had a look.

‘Having a walk around this mountain spot makes me feel closer to my brother again. It makes it more real. I needed to retrace the steps my brother took on the day he was killed. I think about him every day. He was still young, only 50 when he lost his life.

This week, having been afraid for so long to go to the place where his beloved brother died, Zaid al-Hilli finally made the sombre pilgrimage

Saad and Iqbal al-Hilli with one of their daughters. Both parents were killed by a gunman, along with Iqbal’s mother Suhaila-al-Allaf and local cyclist Sylvain Mollier

‘For people who don’t know what happened here, it’s a beautiful place. For me of course this is a beautiful place too, but it will always be tarnished in my mind. Being here leaves a bitter taste in the mouth. It still feels raw. The pain never really goes away.’

The unsolved murders of the al-Hilli family on this remote road have baffled detectives for nearly a decade and a half.

Shortly after 3.45pm on September 5, 2012, Iraqi-born satellite engineer Saad was found dead at the wheel of his car by British cyclist Brett Martin.

Saad’s dentist wife Iqbal lay dead in the front passenger seat; Suhaila on the back seat. The al-Hillis’ eldest daughter Zainab, then seven, was barely conscious on the ground after being shot in the shoulder and pistol-whipped. She would eventually recover from her appalling injuries.

On the ground, several yards from the car, was the body of Sylvain Mollier, who had cycled 20 miles from his home in nearby Ugine to the Le Martinet clearing, where he had paused briefly.

As for the al-Hillis’ younger daughter, Zeena, four, she managed to avoid being spotted as the killer approached the car by cowering under her dead grandmother’s legs in the footwell of the rear seat, hiding behind her skirt.

She was so well hidden that she wouldn’t be found by gendarmes until the following day.

Tourists at the campsite where the al-Hillis had been staying in their caravan told police that the family had two daughters and heat detection equipment used to scan the bullet-strewn car led to a petrified Zeena being found alive.

In total, the gunman fired 21 bullets from a Swiss-issue Luger P06-29 pistol. Ballistics tests showed that Mr Mollier, a factory workshop welder, was struck first and by five bullets, the most of any of the victims.

Last week, after dozens of false leads, several arrests and tens of thousands of hours of police interviews, there were hopes of a breakthrough in identifying the murder weapon.

A pistol similar to the assassin’s Luger was found on the bed of Lake Annecy by two British holidaymakers.

To add to the intrigue, it was retrieved close to the Solitaire du Luc campsite where Saad and his family had been staying.

French prosecutor Marie-Celine Lawrysz, from the cold case unit in Paris which is now overseeing the investigation, confirmed that the semi-automatic pistol found on August 20 was being analysed by ballistics experts.

For Zaid and the other family members, including Zainab, now 21, and Zeena, 18, it represents a tantalising hope.

Shortly after 3.45pm on September 5, 2012, Iraqi-born satellite engineer Saad (pictured) was found dead at the wheel of his car by British cyclist Brett Martin

French police inspect a drain under the road to the murder scene during their investigation in 2012 

Police with the al-Hilli family’s car at the Le Martinet parking layby above Lake Annecy. Saad’s body was found at the wheel of his bullet-ridden BMW estate

Zaid pictured at the spot where the shooting happened. ‘It feels very strange being here,’ he admits. ‘You can hear the river, and I can imagine Saad would have appreciated that. I understand why he would have got out of the car and had a look’

The choice of the Luger pistol has always been one of the most intriguing aspects of the story. Detectives have never been able to explain why an assassin apparently experienced in handling arms – who could shoot at five people in less than two minutes – would choose a gun made before the Second World War that easily jams and had to be reloaded twice during the massacre.

Senior investigators favour a theory that the perpetrator could have been a foreign special forces soldier, such as a member of the elite Swiss counter-terror police force, who went off the rails.

This explanation, however, does not convince Zaid, who relives the tragedy every day.

‘I can’t believe it was all random,’ he says. ‘Why would someone come up here armed with a pistol and several cartridges just hoping that some people would come along that they could kill, and then just disappear?

‘If this person was actually a psycho they would have done it in a town to make an impact, not in a lonely place like this.’

Zaid’s insistence is reinforced by what local sources believe preceded the half-hour drive from the campsite to the clearing. According to one person close to the investigation, Saad only ended up there after missing an earlier turn-off to see a nearby waterfall that had been recommended by one of the campsite staff.

Not only has Zaid had to deal with the grief of losing his brother so brutally, he also had to suffer the indignity of once being the prime suspect.

He was arrested at his home in 2013 on suspicion of murder over claims he might have hired a hitman to kill Saad following a bitter inheritance dispute between the pair involving the Surrey house and their father Kadhim’s estate.

Six months later, police announced there would be no further action. But for Zaid the accusation left an emotional wound.

The two brothers had been inseparable for most of their lives, arriving in London with their parents when they were 12 and ten. Their father, a successful businessman in Baghdad, had to flee Saddam Hussein’s regime. During our conversation, he frequently drifts into the present tense, talking about his brother as though he is still with us.

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Despite the solemnity of the occasion, he can laugh when he recollects the way his younger brother embraced so many hobbies in life. ‘Nowadays people would probably say he has ADHD,’ jokes Zaid. ‘He used to say sleep was a waste of time.’

He recounts fond memories of a previous trip to this region with Saad in the 1970s. ‘Saad had an adventurous streak to him,’ Zaid, a grandfather-of-three, remembers. ‘He used to try to find out things. He loved the countryside, walking and discovering new places. We used to go walking together over the North Downs.

‘Even though this place is remote, hiking here is something we would probably have done if I had been with him, because that’s how we used to live before. We did everything together.’

Until now though, Zaid has been afraid to return to the Alps because of an understandable fear he might be held again due to what he regards as the victimisation he experienced at the hands of the French judicial system.

‘I didn’t think I would ever be here to see the place where my brother was killed. I never thought it would happen, but over time things change.

‘I was afraid to come here for so long because I thought I would be re-arrested. I didn’t trust the French police after what they did to me by making me the scapegoat. My friends told me not to take the risk, so did my lawyers.

‘I think racism had a lot to do with it, because we are from Iraq. The French police came up with all sorts of stupid theories that absolutely had no evidence to justify their claims.

‘Time is a healer though. I’m not in that moment where I was 14 years ago. So, I’m glad I’ve come here. It helps me put everything in perspective and to understand how it happened.

‘Even today I think about it deeply,’ he continues. ‘I think how can such an unnatural thing have happened to my family and me?

‘You realise it’s never going to leave you at any stage. And of course, we haven’t had closure, and that is the other problem.

‘This crime is still going on, it’s still being investigated, so every few months you’re reminded. You’re living those moments as you did 14 years ago.’

Zaid’s view is that the intended victim was always more likely to be Mr Mollier, but that the prosecutor initially leading the investigation preferred to believe the motive lay in the UK.

‘Sylvain Mollier must have been the target,’ Zaid says. ‘This was planned by someone who was waiting because they had information beforehand. Being here now just confirms that for me.

‘Saad’s family were tourists. It’s impossible to imagine they were the targets. I have always held the view they were at the wrong place at the wrong time, not the other way round, as the French authorities tried to suggest.

‘If anybody wanted to harm Saad, they would have harmed him near his house or his work, where they know his movements.’

According to Zaid, his brother might have chatted with father-of-three Mollier or offered help after the chain came off his bike.

Only after the culprit had fired two shots into Mollier did he aim at Saad, who was able to get back into the car and swing it around in reverse before its wheels became stuck in the mud bank at the rear of the parking area.

‘I think that theory is very convincing,’ Zaid adds. ‘No one has come up with anything better to explain what happened.’

Saad al-Hilli with one of his children. At the time of his murder, he would have been preparing to pack up the family’s caravan and drive back to Surrey for his daughters, Zainab and Zeena, to start the new school year

‘Having a walk around this mountain spot makes me feel closer to my brother again,’ says Zaid. ‘It makes it more real. I needed to retrace the steps my brother took on the day he was killed. I think about him every day’

The murder took place near the mountain village of Chevaline, which was visited by Saad and his family

As Zaid and I leave Le Martinet, two cyclists come past. The weather is glorious, just as it was back then. Saad would have been preparing to pack up the family’s caravan and drive back to Surrey for Zainab and Zeena to start the new school year.

‘The most hurtful side of this is that Saad had two young girls,’ Zaid remarks. ‘Now they are both adults, doing their studies, and getting on again with their lives.

‘I think children are more resilient than us adults, but they’ve lost their parents and their grandmother. It’s not something you wish on anyone.’

An hour away, at police headquarters in Chambery, the Alps murders dossiers in the incident room are piled high. Fourteen years’ worth of evidence sits on the shelves.

Some of those dusty files are now being re-examined, perhaps with fresh impetus following the recent gun finding in the lake.

For Zaid – and equally importantly his nieces Zainab and Zeena – a breakthrough cannot come soon enough.

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