Five people on the speedboat with TV actress Nida "Tangmo" Patcharaveerapong before her death will be subjected to a lie detector test, police said yesterday.
Pol Col Chaturon Anurakbundit, head of Muang police station in Nonthaburi, said the five will be summoned for questioning and be subjected to a polygraph test.
"They will be called for a new round of questioning and undergo a lie detector test as soon as possible since people wonder whether they are telling the truth," he said, referring to questions surrounding the circumstances that led to the actress falling into the river.
The actress reportedly went to the back of the boat to relieve herself when she fell in the water on Thursday. Her body was found on Saturday afternoon.
The five people aboad the speedboat were named as Idsarin "Gatick" Juthasuksawat, Tangmo's manager; Wisapat "Sand" Manomairat, Nitas "Job" Kiratisoothisathorn; Tanupat "Por" Lerttaweewit; and Phaiboon "Robert" Trikanjananun.
Mr Tanupat, who owned the speedboat, and Mr Phaiboon, who was driving the vessel, were charged with operating an unlicensed vessel and negligence leading to death.
Pol Col Chaturon said the witnesses will also be asked to reconstruct events prior to the tragedy, adding that further charges could be laid.
He said police have yet to receive an autopsy report and the results of blood tests conducted on the five people on board the speedboat.
National police chief Suwat Jangyodsuk said investigators will look at a reported wound to the actress' thigh and determine whether there was an argument before the incident.
He said the witnesses will be summoned for more questioning while insisting that police are also trying to verify their stories which will also answer lingering questions asked by the public. He said the lie detector test was one option police could use.
Pol Gen Suwat said police will provide protection to the actress' mother if there are grounds to believe she was intimidated.
Pol Col Siriwat Deepor, deputy chief of Technology Crime Suppression Division, said an examination of the actress' phone should be completed this week.