'No stone will be left unturned' - Ex-detective predicts 'detailed forensic investigation' for Swiss police after fatal explosion

At least 40 people have been killed in the explosion, which ripped through the Le Constellation bar at a Swiss ski resort in Crans-Montana.

In a press conference, Swiss authorities confirmed victims "are of several different nationalities", and many of those injured "have severe burns" and the local intensive care unit is "full".

Reacting to the fatal incident, Mr Hurley told GB News: "Once the bodies are all fully recovered and they've started the process of identifying who's who and linking them up with their families, then they will be carrying out a very detailed forensic examination to determine precisely what happened.

"Normally with fires, not only will you deploy crime scene investigators, but you will bring in specialist laboratory scientists from their criminal police laboratories who will be experts at analysing any chemicals or accelerants that might be present."

He added: "It's very difficult this early stage to say what will have caused this. I'm surprised they've said this early that they've ruled out terrorism, because until you know the exact cause of the explosion, you can't rule any particular source of it out.

"But if we assume that it is a mountain village which is unlikely to be served by gas mains, probably they rely on liquid petroleum gas for their heating in those large tanks you'll see out the back of buildings or perhaps containers. And of course, if one of those has been badly managed or leaked, then there's always a chance of an expanding vapour explosion you get with those kind of things. But this is just conjecture on my part."

Assuring that "no stone will be unturned" by the authorities, he said: "Bottom line is, they will be leaving no stone unturned, to work out what the actual cause of the fire was.

"You need to know what initiated it, what was the initial fuel? What were the sources of oxygen for the fire and what then caused it to spread? And of course, we're already hearing there was only one exit, which, of course, I'm almost sure would be a fire violation for a bar of that size in Switzerland."

Mr Hurley continued: "But people get reckless and they don't make sure doors are open to ensure their customers are not placed at additional risk, so this will go on for a good while, this investigation."

As Miriam told Mr Hurley of an eyewitnesses claim that the fire may have been caused by a "sparkler held too close to the ceiling" of the bar, the ex-detective responded: "Undoubtedly in ceilings you get lots of voids, and it's very easy for a fire once it starts to flash right across the open ceiling.

"And I'm sure there will be all kinds of dust and fragments and rubbish up there which will have to act as kindling. But again, this is all conjecture, and I think let's wait and see what happens."

He made clear: "And of course, the other point I make is witness accounts can always be confused.

"So whilst people think perhaps it started with an explosion, it may well be that this eyewitness is correct and it actually started with someone setting the ceiling tiles on fire, fire which later went on then to hit a source of gas."

Detailing the next steps for the authorities in identifying the victims and returning them to their families internationally, Mr Hurley explained: "The first thing that they'll need and they will want to do is identify who are local residents, local nationals and who are not.

"And then there is a system in most countries, certainly within the UK, where they will set up a thing called a Casualty Bureau, where they call in specialist officers and in some cases volunteers to man the phones and handle incoming calls from concerned relatives who may think 'my family is actually at this resort on holiday, we haven't heard from them'."

He continued: "They will then start to collate the details and transfer those across to the Swiss. We live in a modern, totally connected world now with the internet and mobile phone, so the transference of information should not take long. But the Swiss are well organised, a very efficient country as we know.

"And so their emergency service processes for identifying people with mass casualty events will have been regularly rehearsed and well practiced. So effectively, what is a well-oiled machine will fall into place in Germany, Britain, France and so on."

In a statement, a Foreign, Commonwealth & Development Office spokesperson said: "Our thoughts are with all those injured and killed in the terrible tragedy in Crans-Montana, and we pay tribute to the Swiss emergency services who are leading the response.

"We will continue to monitor the situation, and our consular staff stand ready to support any British nationals who may be affected.

"We have not yet received any requests for consular assistance from individuals affected, or their families, but any British nationals in need of consular assistance can call us 24/7, selecting the option for ‘Consular services for British nationals’ on +44 (0) 20 7008 5000, or contact local consular support at www.gov.uk/world/embassies."