BANGKOK – The Criminal Court on Thursday sentenced Sararat “Aem Cyanide” Rangsiwuthaporn to life in prison for the cyanide poisoning death of a police officer in Nakhon Pathom province. Sararat, 39, already has a prior murder conviction, and police have linked her to a wider string of suspected poisonings. Prosecutors say she used cyanide again and again against people close to her.
The ruling, issued on February 20, 2026, adds to a case that has drawn national attention since 2023. Thai media commonly call her “Aem Cyanide” or “Am Cyanide” because investigators say she used potassium cyanide. Over time, her nickname has become tied to one of Thailand’s most disturbing suspected serial poisoning cases.
How the “Aem Cyanide” Case Broke Open
Public focus on the case surged in April 2023 after the sudden death of Siriporn Khanwong, a friend of Sararat’s. The two women had traveled to the Mae Klong River in Ratchaburi province for a Buddhist merit-making activity that included releasing fish. After the ritual, Siriporn collapsed on the riverbank and died. Later, an autopsy found cyanide in her body, and police opened a larger investigation.
After that, investigators started connecting Sararat to other deaths with similar patterns, going back to 2015. Police say she targeted friends, acquaintances, and relatives. Many of them reportedly had money, valuables, or a financial link to her. Authorities allege she mixed cyanide into food, drinks, or herbal capsules. Then, after the victims died, she allegedly took cash, jewelry, or other items.
By the middle of 2023, police said they had tied her to 14 suspicious deaths, and one attempted murder in which the victim survived. Investigators also pointed to a possible motive.
They say Sararat had heavy online gambling debts. Because of that, police believe she borrowed money, took valuables, and then killed to avoid paying people back. Reports also described financial trails showing millions of baht moving through her accounts during the period tied to the alleged crimes.
The case also widened because of Sararat’s former marriage. Her ex-husband, police officer Withoon Rangsiwuthaporn, faced charges after authorities accused him of helping her hide evidence and avoid arrest. He later received a prison sentence for those crimes.
The Poisoning of a Police Officer
This week’s life sentence comes from a separate case involving the poisoning of a police officer in Nakhon Pathom. Public details from the court have been limited. Still, prosecutors convinced the court that Sararat gave the officer cyanide, leading to death. The court convicted her of murder and chose life imprisonment instead of the death penalty. The reason for that choice has not been fully explained in public summaries.
The decision follows her earlier conviction in the first of several trials. In November 2024, the same court found her guilty of murdering Siriporn Khanwong. In that case, the court sentenced Sararat to death after finding she spiked Siriporn’s food or drink during the river trip and then stole valuables worth thousands of dollars.
Even with two major convictions now on record, Sararat still faces many more cases. She has about 13 additional murder trials tied to other alleged victims. She also faces dozens of other charges, including fraud and theft. Thailand often handles multi-victim cases this way, trying each death in separate proceedings.
Quick Facts in the “Am Cyanide” Case
- Suspected victims: 14 deaths linked to cyanide poisoning from 2015 to 2023, plus one survivor of an alleged attempt
- How police say it happened: Victims consumed poisoned food, drinks, or “herbal supplements” during meals or outings with Sararat.
- Possible motive: Financial stress tied to online gambling debts, plus claims of taking money and valuables
- Arrest timeline: Sararat was arrested in April 2023, and the case renewed attention on older poisoning deaths
- Earlier sentence: Death penalty in November 2024 for the murder of Siriporn Khanwong (first trial)
- Latest sentence: Life imprisonment on February 20, 2026, for the poisoning of a police officer in Nakhon Pathom
- Scope of charges: Around 80 offenses across multiple trials
The story has rattled people across Thailand. Many have focused on how easily trust can break down in close relationships. Others have pointed to the access to dangerous poisons like cyanide. At the same time, the case has raised concerns about how earlier suspicious deaths were handled. Media coverage has stayed intense, and Sararat’s calm public appearances have added to the anger and attention.
What This Means Next, And Why the Case Still Isn’t Over
Because the case ranks among Thailand’s most widely discussed suspected serial killing investigations in recent memory, it has also pushed policy talk. Some have called for tighter controls on toxic substances. Others want stronger coordination when police review poisoning deaths, especially when patterns show up across provinces and years.
Sararat continues to deny wrongdoing across the cases. Still, convictions in at least two trials have confirmed her status as a convicted murderer. After this life sentence in the police officer case, th focus now shifts to the remaining trials. Prosecutors are expected to keep pursuing convictions tied to the full list of alleged victims.
For now, the Bangkok Criminal Court’s latest decision adds another grim entry to a case that keeps unfolding in public view. As more hearings move forward, Thailand continues to watch for how the courts handle the rest of the charges in what many see as the country’s most notorious cyanide poisoning case.
