NAKHON PATHOM, THAILAND – A criminal court acquitted alleged serial poisoner Sararat Rangsiwuthaporn in another cyanide-related case, ruling that the evidence did not prove she had administered the toxin beyond reasonable doubt.
The third verdict in a sprawling murder series
The newly concluded trial was the third case to reach a verdict in what authorities described as one of the country’s biggest suspected serial murder investigations. Judges found that prosecutors had not shown Sararat’s guilt to the standard required for a conviction.
The court therefore cleared her of the charges in this file, noting that both the available evidence and forensic findings were too weak to establish deliberate poisoning.
What prosecutors alleged
Prosecutors had accused the defendant of premeditated murder, claiming she gave Nittaya Kaewbuppha (36) a cyanide-laced drink between 22 and 23 August 2020. According to the indictment, the victim died from circulatory and respiratory failure consistent with poisoning.
The prosecution also alleged that Sararat subsequently took the victim’s Honda car and other belongings. These actions were presented as proof of a robbery motive linked to the alleged killing.
Forensic gaps and missing cyanide tests
A forensic physician testified that no cyanide test was carried out during the original autopsy, because investigators at the time did not suspect poisoning. This meant no direct toxicological proof of cyanide exposure existed from the period immediately after the woman’s death.
A toxicologist later told the court that the victim’s symptoms were compatible with cyanide exposure. However, judges assessed this as circumstantial and not conclusive enough to support a murder conviction.
Disputed theft motive
The court also identified uncertainties in the alleged theft of the vehicle, undermining the prosecution’s suggested motive. According to the ruling, it was possible that the deceased had pledged vehicles to Sararat as collateral for a loan.
Such an arrangement could legally explain why Sararat had possession of the car and other items, weakening the argument that she had stolen them after a killing.
Cyanide order dated two years after death
Judges further pointed to evidence indicating that potassium cyanide was ordered by the defendant in August 2022, around two years after Nittaya’s death. The timeline created additional doubt about the prosecution’s theory of the case.
The court concluded that prosecutors had not proved Sararat possessed the poison at the alleged time of the crime in 2020. This temporal gap was a key factor in the decision to acquit.
Why old poisoning cases are difficult
The ruling highlighted the challenge of proving poisoning years after a death that was initially classified as natural. Once a case is treated that way, crucial forensic steps, such as targeted toxicology testing, are often not carried out.
Missing or incomplete samples from the early phase of an investigation can make later chains of circumstantial evidence vulnerable to attack. Even when a pattern seems to emerge, courts may consider it insufficient without hard scientific proof.
Charges dismissed but detention continues
Despite the acquittal, the court dismissed all criminal counts and related civil claims in this particular case. The decision did not, however, lead to the defendant’s release.
Judges ordered that Sararat remain in custody pending a possible appeal. Her ongoing detention was linked to the wider series of cases still before the courts.
Investigation spanning years and provinces
The defendant was arrested in 2023 after the suspicious death of a friend prompted police to re-examine several earlier unexplained fatalities. That review led investigators to reopen cases stretching back years.
Police have spoken of alleged offences between 2015 and 2023 in multiple provinces, including Nakhon Pathom and Ratchaburi. They cited at least 14 possible deaths and one surviving victim, whose account was said to reveal a recurring pattern.
Prior death sentences and ongoing trials
In two other cases, Sararat had already been convicted before the latest verdict. In November 2024 she was sentenced to death for the murder of Siriporn Khanwong.
In February this year, she received another death sentence in a separate poisoning case, which was later reduced to life imprisonment. More than a dozen additional individual cases from the wider investigation were still pending before the courts.