The Central Investigation Bureau is seeking help from the US Federal Bureau of Investigation to assist with their probe following the arrest and conviction of child serial killer Nui.
The FBI's Behavioral Analysis Unit will visit Bangkok next week to pass on tips on how to catch serial killers, amid concerns their probe into the so-called Nui case, which ended in a court conviction last week, may have overlooked some victims.
The FBI team would take up Nui's case as a case study for Thai investigators, CIB chief Pongsapat Pongcharoen said.
The case is also known as the Nong Cartoon case, after the six-year-old fell victim to 36-year-old Nui, alias Ting Tang.
Nui was convicted of raping and murdering the young girl, whom he lured from a pickup truck at a concert near Sukhumvit soi 105 (Soi Lasalle), close to the Bearing BTS station, on Dec 6 last year. Nui has no last name or identification card.
On March 27 Phra Khanong Provincial Court sentenced him to death but this was reduced to life in jail because he confessed. He admitted to having killed at least four children and said he molested more than 10 child victims, Pol Lt Gen Pongsapat said.
He committed the crimes after being discharged from prison where he had served three years for separating a minor from his guardians.
Pol Lt Gen Pongsapat said the FBI experts would advise on how to investigate serial murder cases properly.
Thai investigators could have missed some points in their efforts to broaden their probe, he said.
Thai police, for instance, could have missed some clues which might have led to the discovery of more of Nui's victims, Pol Lt Gen Pongsapat said.
"There are many mentally ill people out there and we hope this study will shed more light on the behaviour of this specific group of potential criminals," he said.
Pol Lt Col Songrak Khunsri, deputy chief of the Crime Suppression Division's (CSD) Region 6, said two representatives of each the nine regional offices of the CSD would attend the FBI training.
The FBI team would show investigators how to form a framework for the Nong Cartoon case, Pol Lt Col Songrak said.