The parents of a woman who died alongside her fiance after drinking contaminated limoncello have said they are desperate for justice.

Greta Otteson, 33, and Arno Quinton, 36, were found dead on Boxing Day in Hoi An, Vietnam, as a result of methanol poisoning.

Hours earlier, Greta had messaged her parents, Paul and Susan Otteson, to say she had “the worst hangover ever” and was going to lie down, but she never woke up.

The barman who allegedly made the limoncello was arrested in February and is being held without charge. The family said they have had no further updates from the police.

“It’s about accountability,” said Paul, adding: “We can’t move on.”

Da Nang City Police has been asked to comment.

Methanol is a type of alcohol commonly found in cleaning products, fuel and antifreeze.

It is similar to ethanol, which is used for alcoholic drinks, but it is cheaper and more toxic to humans because of the way it is processed by the body.

In Mr and Mr Otteson’s home in Rhandirmwyn, Carmarthenshire, two square bags sit next to the stairs – one has a pink bunny sitting on top, the other, a blue teddy.

They hold Greta and Arno’s ashes.

“They sit in the lounge with us,” said Mr Otteson, a retired project manager. “We want to put them to rest, but we feel we can’t do that until we get a proper conclusion.”

Greta had been living in Hoi An with Arno, her South African partner of about two years, where the couple ran a villa renting out rooms to travellers.

She was an only child, described by her father as “marvellous”, a “free spirit” and a “hard worker” who studied in Cardiff, Paris and Los Angeles.

In November 2024, Paul, 71 and Susan, 70, had travelled to Vietnam, meeting Arno for the first time, and the couple announced their engagement shortly afterwards.

“It was lovely – we were so happy,” said Paul, who described Arno as “quiet but highly intelligent” and someone he “would have loved to have as a son in law”.

During their stay, the family ate a number of times at Good Morning Vietnam, a well known Italian restaurant, where they enjoyed the food and received free shots of homemade limoncello at the end.

A few weeks later, when Paul and Susan had left Vietnam and were trying to think of a Christmas gift for Greta and Arno, they remembered the restaurant and its bottles of limoncello and decided to order a few of them for delivery to their daughter’s house.

It was a decision that would have the most devastating consequences.

Within hours of drinking the limoncello, Greta messaged her parents on Christmas Day to say she had a terrible hangover and was seeing black spots but brushed off suggestions from them, and a friend who had visited, to get medical help.

Greta and Arno were found dead in separate rooms of the villa on Boxing Day. Hours later, Paul and Susan were on a plane to Vietnam.

Paul recalled the intense social media speculation that followed as well as the struggle to navigate the practicalities of dealing with a death in a foreign country.

It was not long before post mortem examinations revealed Greta and Arno had died from severe methanol poisoning.

In February, police arrested a barman who worked in a restaurant in Hoi An for “violating regulations on food safety” by “using used 70-degree medical grade alcohol, along with filtered water, lemon peel and white sugar to create two bottles of limoncello”.

According to the Vietnamese central government, the offence could carry a maximum prison term of seven to 15 years.

Hundreds of people are poisoned by methanol every year in South East Asia, according to the charity Doctors Without Borders (MSF).

Greta and Arno’s deaths came just weeks after six people died of methanol poisoning in Laos, a country which neighbours Vietnam.

Paul and Susan were warned investigations take a long time in Vietnam, with the possibility of a suspect being held for a year before being charged or released.

They said the wait for answers was becoming unbearable.

“We just want justice,” said Paul.

“We can’t move on. Susan’s asking me every morning when we wake up, ‘is there any news? Is there any news?’ I have to say ‘no, nothing yet’.”

“It’s about accountability,” he added.

“Justice for us would be naming the people responsible and prosecuting them.”

The couple said they also felt “very upset” the restaurant where they had ordered the limoncello was still open and had not publicly apologised.

“They just carried on as if nothing has happened,” said Paul.

Good Morning Vietnam did not respond to requests for comment from BBC News.

For Paul and Susan, the pain is still very raw.

Paul becomes emotional talking of his regret that they will never have grandchildren and that Arno will never come to Wales.

“Everything that we’ve worked for over 40 years, it was all for Greta and Arno eventually, but now it’s meaningless,” he said.

Once the police investigation is concluded, Greta and Arno will finally be laid to rest.

The location is undecided, but the family said they would always be together.

Foreign Office minister Seema Malhotra said she was “deeply saddened” by the case and that her thoughts were with the family.

“We know that methanol poisoning and counterfeit alcohol pose a serious, life-threatening risk to British travellers in some parts of the word. This is a deeply concerning issue and we are committed to helping keep people safe,” she said.

“We are tackling this issue head-on, working with local authorities and over 150 travel industry partners to raise awareness of the dangers of methanol poisoning.”

Additional reporting by Gareth Bryer