For Australian friends Bianca Jones and Holly Bowles, it was their first big trip venturing out to explore the world.

Like so many 19-year-olds, they were drawn to the romance of backpacking across South East Asia – where food is great, people are friendly and the scenery stunning.

They had “saved up enough money after school and university to have their overseas jaunt, as so many of our kids do,” said their football team coach Nick Heath. “And off they went.”

They ended up on 12 November in the riverside town of Vang Vieng in central Laos.

The two checked into the popular Nana Backpacker Hostel – where guests often receive a free shot upon arrival. Days later both were on life support in hospitals in Thailand.

Jones’s death was announced on 21 November, and Bowles’s a day later. The death of a British woman, 28-year-old Simone White, was also announced on Thursday.

They are among six foreign tourists who have died from what is believed to be a mass incident of methanol poisoning in Vang Vieng.

Two Danish women, aged 19 and 20, died last week, while an American man also died. They have not been identified.

It is unclear how many others have fallen ill, but a transnational police investigation is now underway into the deaths.

Much of the scrutiny has fallen on the hostel where some of the victims were reportedly staying. The girls had taken free shots there before heading out for the night.

The hostel manager has denied culpability, saying the same drinks had been served to at least 100 other guests that night who reported no problems. The manager was taken in by police for questioning on Thursday.

Mr Heath, who spoke to media on behalf of Ms Bowles’s family, said they knew it was methanol that caused the girls to fall ill. But “no one really knows how and where it entered their system”.

To understand what happened, the BBC spoke to backpackers and a diplomat about the area.

Our reporting found the town where travellers fell ill remains a party hotspot despite past efforts, with some success, to clean up its image, and that while the risk of methanol poisoning is known among consulates and tourism operators, travellers appear largely ignorant.

Vang Vieng – a tiny town on the Nam Song river surrounded by limestone mountains and paddy fields – is known for its scenery.

It is also known as a party town – a reputation Laos officials have been trying to shed over the past decade.

A four-hour bus ride from the capital Vientiane, it has long been the stopping point on the Banana Pancake Trail backpacking route between Thailand, Laos, Cambodia and Vietnam before heading north to the ancient temples of Luang Prabang.

In Vang Vieng, hostel bunks are advertised at less than €10 (£8) a night, while a bucket of beer can cost half that. Drugs like marijuana and mushrooms are in ready supply, openly advertised at cafes and diners.

During the early 2000s and 2010s the town was famous for hardcore partying and as a spot for riding inflatables down the local river. But after several tourists were injured or died, efforts were made at raising safety standards.

“To combat the river tubing deaths they demolished a bunch of the riverside bars that were selling buckets of vodka to people floating by,” one Western diplomat in the region told the BBC.

Laos officials aimed to re-centre the town as a spot for eco-tourism rather than just a hub for the young and drunk.

“And it worked,” they say. “It’s actually changed a quite a lot in the past decade, they’ve cleaned it up, it’s way more modern than it used to be.”

But because of that: “I think it can be very easy for young travellers to miss that this is still a very poor country with lax regulations and safety standards.”

The diplomat said methanol poisoning – where alcoholic drinks are contaminated with a toxic compound – is well-known among consulates and tourism operators.

Consulates are fairly regularly having to deal with cases of tourists who have fallen ill from dodgy drinks, the diplomat noted.

South East Asia is documented as the worst region for methanol poisoning. Local producers making cheap alcohol often will not correctly reduce the toxic level of methanol produced in the process.

Thousands of incidents are recorded every year in the region, according to Doctors Without Borders (MSF).

But for tourists, awareness around poisonous alcohol is low.

British backpacker Sarisha told the BBC’s Newsbeat programme that people did not seem to consider the risks of free drinks when she was recently staying at Nana Backpacker.

Like most other hostels, happy hours were a daily staple at the venue as well as free shots of local vodkas as courtesies, she said.

“It’s a very party city,” she said.

Tourists still in town are now taking extra precautions after the shocking deaths.

On Friday, Miika, 19, a Finnish backpacker staying at a hostel just 10 minutes walk from Nana Backpacker, told the BBC he and his friends had arrived in town two days ago. They were now only ordering bottled beers and rethinking river tubing because shots were included.

“Now because we know about this, we didn’t really want to go there,” he said.

British woman Natasha Moore, 22, told the BBC she cancelled her booking for Nana Backpacker after hearing about the deaths.

“It’s just so scary, I feel so overwhelmed… it feels like I’ve escaped death, almost like survivor’s guilt”, she said in a TikTok video warning other travellers.

Her group arrived in the town two days after the poisoning, where “it was still kind of hush hush, nobody really knew too much about what was going on”.

She knew many travellers decided to skip the town and said there were signs in the hostel warning to be careful about drinks.

She said she “can’t even count how many free drinks” she had on her travels, but over five nights in Vang Vieng, she and her friends had no free drinks or spirits, only bottled alcohol.

“I feel so, so sad and upset for all the friends and family and the people still in hospital. It’s just so unfair, we were just trying to have a good time,” she said.

“We’ve worked hard to save up to go travel, like it’s such a brave thing to do, and then something like that can happen.”

Additional reporting by Gavin Butler, Amy Walker and Jack Gray