Cyanide killings the deadliest in Thai crime history
The case of suspected serial killer Sararat “Am” Rangsiwuthaporn, 36, could be considered the deadliest in Thailand’s crime history as the alleged crimes were committed over four years without raising any suspicion in the relatives of the victims.
Sararat allegedly poisoned her victims, most of whom she knew personally, mixing the deadly chemical cyanide on items of consumption, such as food, beverages and medicines, posing difficulties for police in their investigation.
A trail of murder
Police believe Sararat poisoned 14 victims (12 women and two men) to allegedly steal their valuables and escape the debt she owed them. However, it turns out that the number of victims who may have been poisoned by the suspect could be more than 20 people.
One victim – Kantima Paesaard, 36 – survived the alleged poisoning attempt and alerted the police.
The deaths occurred between December 2020 and April 2023, across eight provinces — Nakhon Pathom, Kanchanaburi, Ratchaburi, Phetchaburi, Udon Thani, Samut Sakhon, Mukdahan and Bangkok.
The case came to light after a Kanchanaburi businesswoman, Niphawan Khanwong, 32, reportedly joined Sararat on a trip to a temple in Ban Pong district of Ratchaburi province on April 14, and suddenly collapsed and died soon after. Autopsy results showed heart failure as the cause of the death.
Another case that became a point of interest among people was the death of Sararat’s common-law husband, Suthisak Poonkwan, 35, who died on March 12 at his residence in Udon Thani province before celebrating the suspect's birthday.
The cause of Suthisak's death was said to be cardiac arrhythmia, the police said. Gold jewellery worth over 100,000 baht and an unknown amount of cash were reportedly missing following his death.
Forensic tests of two bodies showed traces of cyanide in the blood.
Traces of cyanide were also found inside Sararat's car, at her sister's residence in Ratchaburi, and in items at the Nakhon Pathom residence of Pusadee Samboonmee, 39, another suspected victim.
Police found that the suspect had allegedly bought cyanide online from an unidentified company whose factory is located in Bangkok’s Lat Krabang district. They added that up to 100 people, including superstars and nurses, had bought cyanide from this company.
Police investigators said they intend to call 10 people who had ordered cyanide in the same lot as Sararat for questioning on the reason for the purchase, adding that they would investigate whether any Department of Industrial Works officials were involved in the case.
Police allege that Sararat stole her victims' belongings, such as smartphones, gold ornaments, amulets and cash as she had run up debt. Up to 20 people transferred cash into her bank accounts before dying under suspicious circumstances, the police added.
They also suspect that Sararat might have had an accomplice, as she committed the alleged crimes on weekends, when she travelled with the suspected victims to cloud the evidence trail.
Sararat was arrested by crime suppression police officers at the Chaeng Watthana Government Complex in Bangkok on April 25. She is being detained at the Central Women Correctional Institution in Bangkok’s Chatuchak district.
Pol Lt-Colonel Withoon Rangsiwuthaporn, Sararat’s ex-husband, surrendered to the police on Wednesday (May 3) following an arrest warrant issued by Nakhon Pathom Provincial Court.
He is suspected of being the alleged accomplice who helped Sararat commit the alleged murders. He reportedly told police that Sararat had asked him to pick up Suthisak's car from Udon Thani. Withoon then drove the car to Nakhon Pathom, where Sararat sold it to a pawnshop in the province.
Withoon was suspended as deputy superintendent at Ratchaburi’s Ban Pong Police Station. He was initially charged with embezzlement and using fake government documents.
However, the court granted Withoon bail on 100,000 baht surety on Thursday (May 4), with a condition that he be fitted with an electronic monitoring bracelet.
Serial killers in Thailand
Sararat, who is dubbed as "Am Cyanide" by Thai media outlets, if convicted, could be the deadliest serial killer in Thai crime history with the most number of deaths.
Psychologists believe that serial killers who murder at least three people have antisocial personality disorder. Many serial killers have problems with their background, such as being assaulted or humiliated about their social status. The experiences make them commit crimes similar to what they had faced.
Boonpeng Heep Lek killed between two and seven religious worshippers in 1917. Convicted for these killings, he was beheaded in 1919, the last public execution in Thailand.
Nirut Sonkhamhan, or “The Pickup Truck Killer”, poisoned nine taxi drivers from 2011 to 2012, six of whom died. He was arrested and charged with the murders, but hanged himself in his jail cell before he could go on trial.
Following the cyanide serial killer case, the Public Health Ministry has allowed police investigators to order full autopsies in cases where the cause of death has not been determined. Family members of the deceased will not be charged for the cost of the autopsies.
Police investigators are checking various issues relating to the case, such as her accomplice, criminal bank accounts, and the motivation for the alleged crimes.
Sararat has so far been charged with premeditated murder and theft. She faces the death penalty for premeditated murder, but she may be spared capital punishment because she has reportedly been diagnosed with a mental disorder and is pregnant.