According to Thai government records, Si Ouey engaged in cannibalism during the war, eating parts of his fellow soldiers when supplies ran low during a siege.

[1][2][3][5] During the 1950s, Si Ouey worked in a number of menial roles (several sources describe him as a gardener) before allegedly beginning his killings.

From 1954 to 1958, Si Ouey was accused of killing several (sources disagree on whether four,[6] five,[6] or six[4]) Thai children, allegedly disembowelling, boiling, and eating his victims.

Active in Bangkok, Nakhon Pathom, and Rayong, Si Ouey was arrested (reportedly while attempting to burn a body)[7] by Thai police in 1958 after which he purportedly confessed to the murders.

[10] Several note that Si Ouey spoke no Thai and as such may not have given an accurate confession, and that he was forced to use a translator during his trial.