A Thai woman believed to be among the worst serial killers in the kingdom’s history was convicted and sentenced to death Wednesday for poisoning a friend with cyanide, in the first of her 14 murder trials.

Sararat Rangsiwuthaporn, 36, an online gambling addict, is accused of swindling thousands of dollars from her victims before killing them with the chemical.

A court in Bangkok convicted her Wednesday for fatally poisoning her friend Siriporn Kanwong.

The two met up near Bangkok in April last year to release fish into the Mae Klong river as part of a Buddhist ritual.

Siriporn collapsed and died shortly afterwards and investigators found traces of cyanide in her body.

Police were then able to link Sararat to previously unsolved cyanide poisonings going back as far as 2015, officers said.

‘The court’s decision is just,’ Siriporn’s mother, Tongpin Kiatchanasiri, told reporters following the verdict.

‘I want to tell my daughter that I miss her deeply, and justice has been done for her today.’

Sararat Rangsiwuthaporn, an online gambling addict from Thailand, was convicted and sentenced to death Wednesday for poisoning a friend with cyanide

Thongpin Kiatchanasiri, mother of Siriporn ‘Koy’ Khanwong, holds a picture of her daughter, who was poisoned by  Sararat Rangsiwuthaporn, outside the Criminal Court in Bangkok, Thailand today

Thongpin Kiatchanasiri, mother of Siriporn ‘Koy’ Khanwong, holds a picture of her daughter while talking to the media outside the Criminal Court in Bangkok

In 2023, the country was rocked by reports of a serial killer who had poisoned 15 people with cyanide. 

Sararat, or ‘Am Cyanide’ as she would later be called, poisoned 15 people who she owed money to and became the country’s first female serial killer.

Police said Sararat funded her gambling addiction by borrowing money from her victims – in one case as much as 300,000 baht (nearly $9,000) – before killing them and stealing their jewellery and mobile phones.

She lured her victims – one of whom survived – to take poisoned ‘herb capsules’, they said.

Sararat faces 13 more separate murder trials, and has been charged with around 80 offences in total.

Her ex-husband – a police lieutenant-colonel – was given 16 months in prison and her former lawyer two years for complicity in Siriporn’s killing, the lawyer for the victim’s family said.

Thailand has been the scene of several sordid and high-profile criminal cases.

Last year, the son of a Spanish actor was accused of killing and dismembering the body of a renowned Colombian plastic surgeon on the tourist island of Koh Phangan. 

Sararat Rangsiwuthaporn is escorted by police officers at a police station in Bangkok, Thailand, April 25, 2023.

More recently, six foreigners were found dead in a luxury Bangkok hotel after a cyanide poisoning believed to be connected to debts worth millions of baht.

US citizen Sherine Chong, 56, is thought to have poisoned herself and five other people with cyanide after she accrued huge debts related to an investment in a hospital in Japan.

She had allegedly convinced a married couple and two other victims among the dead to pour funds into the project, but they had reportedly lost some 10 million baht – roughly $280,000 or £215,000 – as a result.

The deceased – three males and three females of Vietnamese origin aged between 37 and 56 – had last been seen alive when food was delivered to their room at the Grand Hyatt Erawan on Monday afternoon.

The group had arrived at the hotel one day earlier, but on Monday they all moved into Chong’s suite – room 502.

Footage obtained by Vietnamese media revealed the moment the five victims made their way to the room that unbeknownst to them would become the scene of their deaths.

Suspected killer Chong, who was described as ‘stressed’ by hotel staff, was also seen wearing a colourful patterned dress in hotel lift security footage hours before meeting the rest of the group.

Staff delivered food ordered by one member of the group at 2pm on Monday afternoon, along with pots of tea. They offered to brew and serve the drinks but Chong allegedly declined, telling them she would take care of it.

All six people were found dead by hotel staff a day later at 5pm by staff after they failed to check out.

Post-mortem tests confirmed traces of cyanide were found in the cups and in the bodies of the victims, two of whom – including Chong – were American citizens.