Sararat Rangsiwuthaporn, born in 1988, became infamously known as "Am Cyanide" due to her method of poisoning victims with cyanide. Details about her early life remain scarce, but it is known that she struggled with significant gambling debts, which played a crucial role in her criminal activities. ​

Between 2015 and 2023, Sararat orchestrated a series of poisonings resulting in the deaths of 14 individuals. Her victims were predominantly friends and acquaintances from whom she had borrowed money or sought financial gain. She would invite them to partake in meals or religious rituals, during which she administered cyanide into their food or beverages. 

The sudden and unexplained deaths of these individuals initially went unnoticed as foul play. The case gained significant attention following the death of her friend, Siriporn Khanwong, on April 14, 2023. Siriporn collapsed and died after a meal with Sararat during a Buddhist merit-making event in Ratchaburi province. Suspicion arose when Siriporn's belongings, including cash and personal items, were found missing.

Sararat was arrested on April 25, 2023, after an investigation linked her to multiple suspicious deaths. Authorities discovered cyanide in her possession, and forensic tests confirmed the presence of the toxin in the victims' bodies. Her trial commenced in mid-2024, with the first verdict delivered on November 20, 2024, where she was found guilty of premeditated murder and sentenced to death. Her ex-husband, a former police officer, was also convicted for aiding in concealing evidence and received a prison sentence.

As of February 2025, Sararat remains on death row in Thailand, awaiting further legal proceedings related to the additional murder charges pending against her.