Thai woman arrested for allegedly killing 5 with cyanide

Photo via Facebook/ ตำรวจภูธรจังหวัด ราชบุรี

A Thai woman has been arrested for the alleged poisoning and killing of five people using cyanide. The arrest was made after the sudden and unexplained death of the alleged murderer’s most recent victim, Siriporn “Koy” Khanwong, a 32 year old Thai woman from the central province of Ratchaburi, on Saturday, April 1.

Koy was found dead at the Baan Pong Pier in Ratchaburi at 9am on Friday, April 14. Koy reportedly went to the pier to make merit by releasing fish into the river with her Thai friend, later identified as Sararat “Am” Rangsiwuthaporn.

The vendor who witnessed the incident reported that Koy went to the pier to release the fish alone and suddenly fainted. The rescue team came to the spot and provided her with CPR, but she did not respond to the operation. Koy was sent to the hospital and later pronounced dead from a heart attack.

The vendor revealed that she was curious why Koy’s Thai friend, Am, did not come to help her and disappeared from the scene.

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The CCTV cameras at the place featured Koy and Am getting out of Am’s Toyota Vios sedan. The victim held a plastic bag of fish and went directly to the pier. However, the alleged murderer did not go with her. Instead, the Thai woman walked back and forth, as if she was waiting for someone.

Koy fainted at the pier, but the footage showed that Am did not go to her aid, instead, she drove off with the victim’s belongings and mobile phone.

Koy’s family was curious about her death as well and believed that the death was murder and that Koy’s friend, later identified as Sararat “Am” Rangsiwuthaporn, was involved.

Koy’s sister, Nipawan “Som” Khanwong, reported that she learned that her sister went to the pier with Am because Koy posted about it on Facebook. She contacted Am immediately to ask about Koy, but Am claimed she had not gone to the pier with Koy and was in another province.

Som said Am did not do anything suspicious. She kept asking her about Koy and expressed concern about the issue. Som did not suspect Am until the officers confirmed to her that they found Am on CCTV cameras.

Koy’s mother, 63 year old Thongpin Kianchanasiri, revealed that Am borrowed 50,000 baht from Koy but she did not know whether Am paid it back or not.

The family then sought help from the Deputy Commissioner of the Royal Thai Police (RTP), Surachate “Big Joke” Hakparn. A thorough investigation of the case was conducted until the officers discovered that four other victims, who had close contact with Am, all passed away mysteriously. Three of the four people reportedly died from heart attacks similar to Koy.

The first deceased was a police officer named Kanda Torai who passed away on August 10 of last year after investing in a business with Am.

The second one was a teacher who died in September of last year after giving gold necklaces worth about 1 million baht to Am to invest in her business.

The third person was Am’s ex-boyfriend, who passed away on March 12 of this year. Am claimed to the deceased’s family that she was pregnant with the man’s child. So, the family gave her cash, a valuable amulet, and a gold necklace worth about 260,000 baht.

The fourth person was a police officer who frequently visited temples with Am. She fainted and passed away at a temple in the central province of Nakhon Pathom, and her assets disappeared.

After an investigation, officers later confirmed that Am was involved in Koy’s death and arrested Am today at 11am. Officers believe that Am poisoned Koy with cyanide to steal Koy’s assets.

Am was initially charged with Section 288 of the Criminal Law: intentional murder. The penalty will be life imprisonment or imprisonment for 15 to 20 years. Further investigation will be conducted to see whether Am was involved in the deaths of the other four deceased or not and how exactly she operated to kill her victims.


Murdered poisoned friend for assets
The suspect, Sararat “Am” Rangsiwuthaporn | Photo via MGR Online

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Petch Petpailin

Petpailin, or Petch, is a Thai translator and writer for The Thaiger who focuses on translating breakingThai news stories into English. With a background in field journalism, Petch brings several years of experience to the English News desk at The Thaiger. Before joining The Thaiger, Petch worked as a content writer for several known blogging sites in Bangkok, including Happio and The Smart Local. Her articles have been syndicated by many big publishers in Thailand and internationally, including the Daily Mail, The Sun and the Bangkok Post. She is a news writer who stops reading news on the weekends to spend more time cafe hopping and petting dwarf shrimp! But during office hours, you can find Petch on LinkedIn and you can reach her by email at

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