Relatives of Chuwong Sae Tang petitioned the National Police Office Tuesday to change the head of the city police investigation team responsible for probing the death of the 50-year-old construction tycoon.
Wanpen Thanathamsiri and Kan Sae Tang, Chuwong's sister and son, respectively, said they were concerned the police investigation team might lack impartiality in handling the case after learning the team leader, Pol Col Thaweerach Srithawachpong, deputy chief of the Metropolitan Police Bureau's Division 4, was close friends with the former deputy commerce minister Banyin Tangpakorn.
Mr Tangpakorn had been driving the car Chuwong was in when it crashed into a tree on Chaloem Phrakiat Road in Prawet district on June 26, leaving Chuwong dead in the passenger seat.
Pol Col Taweerach was found to be a classmate of Pol Lt Col Banyin at the Royal Police Cadet Academy, said Anek Khamchum, a lawyer representing Chuwong's relatives.
The relatives' request came after Pol Col Taweerat told reporters on Monday that a second investigation had found Chuwong was probably killed in the car accident.
Pol Col Taweerat said the team had looked into every point raised by Chuwong's family, but nothing suspicious was found. A re-examination of the evidence from both the Scientific Crime Detection Division and the Institute of Forensic Medicine confirmed the car crash was an accident, he said.
But assistant police chief Prawut Thawornsiri said Tuesday no final conclusion has been made whether Chuwong was killed in the car accident, or if it was murder. Police were still waiting for automobile experts to provide an analysis.
Pol Lt Gen Prawuth admitted it was suspicious that irregularities had been detected in Chuwong's share transfers.
Shortly before his death, a 25-year-old trainee stock broker received a bank transfer of 30 million baht from Chuwong's assets. A 26-year-old model and former golf caddie, seven months pregnant, received more than 200 million baht worth of shares. Both told police they had had affairs with Chuwong.
The shares have been frozen pending further investigation, he said.
National police chief Somyot Pumpunmuang said that as far as he was concerned there were no sound reasons to change the investigation team's head.
But if Chuwong's death proves to be a murder, no one will be able to help Pol Lt Col Banyin, he added.
The Crime Suppression Division (CSD) is conducting a separate investigation into complaints by the family, including Chuwong's share transfers to non-family members, he said.
Chuwong's family has submitted copies of the share transfer documents and an audio clip of Chuwong's voice, recorded one day before his death, to CSD investigators, who will check if the voice matches that of the man who ordered the shares transferred at a stock brokerage firm.