Lake Annecy is so beautiful and peaceful that it is easy to imagine that bad things can’t happen here.

Today, the mist is sitting over the water and, in the distance, there are mountains reaching into the sky.

It’s picture postcard pretty in the actual sense that there are lots of postcards of this scene.

But take a detour away from the lake and turn towards Doussard. Carry on beyond Chevaline, and you find a different story – an echo of the horrible murders that still linger in people’s memory here.

As we drive along, the snow builds on the verges and the road becomes icy and rapidly quite treacherous.

Not many vehicles come this way. Even in the summer tourist season, this is an unfamiliar route, carving its way through the woods.

But back in September 2012, this is where four people were brutally murdered in one of France’s most notorious unsolved crimes.

Three of them were members of the same British family – Saad al-Hilli and his wife Iqbal, along with Iqbal’s mother, Souhailia al-Allaf. The fourth victim was Sylvain Mollier, a local man who was out on a bicycle ride.

The Al-Hilli family were on holiday, camping at a nearby site. They had been out on a drive and had apparently stopped in a lay-by to enjoy the view. While they were there, Saad, Iqbal and Souhaila were all murdered, along with Mr Mollier.

The Al-Hillis’ two daughters, Zainab and Zeena, both survived.

Zainab, who was seven, was shot in the shoulder and then clubbed by the killer, using his pistol, having possibly run out of ammunition.

Zeena, just four at the time of the attack, escaped injury after hiding beneath the clothing of her dead mother and grandmother in the back of the car.

No motive has ever been established. Indeed, we don’t really know if Mr Mollier was shot because he had witnessed the murders of the family, or vice versa.

The investigation grew from France to Britain, then Switzerland, Spain and beyond. In the end, its tentacles spread to 15 countries.

Saad al-Hilli’s brother was detained after it emerged that they had argued over money.

But the police said there was insufficient evidence against him.

In France, a photofit was created of a motorcyclist who was seen near the crime scene wearing a distinctive crash helmet.

After a painstaking inquiry, he was tracked down, claiming that he hadn’t noticed news about the case, despite enormous media coverage. He, too, was subsequently released.

The years passed, with no apparent breakthrough.

A few months ago, a reconstruction was staged, apparently to confirm timings and to see who could have been where, when. And then, dramatically, this week came the news that the motorcyclist had been arrested once more.

We know he is a man in his late 50s, who lives in a suburb of Lyon.

He was brought in for questioning at Chambery police station amid an explosion of interest.

His detention was extended and then, as suddenly as he had been arrested, the prosecutor announced the man had been released, and eliminated from the inquiry.

Another false dawn, then, in the story of this unsolved crime.

In a small cafe near Doussard, the customers are talking about the case as we walk in.

“Who knows who did it – it might be someone from round here,” says one patron.

The one thing about these murders that everyone agrees upon is that nobody really knows.

“When I saw that a man had been arrested, I was reassured and I really thought it could be him, so this case could be solved,” says a local woman, enjoying some food and a lunchtime drink.

“And now we are back to square one, with a family who will never know if anybody will be arrested and found guilty for these deaths.”

She’s right.

It does feel as if this case has gone back to where it started, with a mass of questions and no answers.

But at least there is some solace – nearly a decade after these horrendous, brutal and baffling murders, the police are still hunting for the killer.