Police have turned down a request by the family of the late businessman, Chuwong Sae Tang, for a change of lead investigator working on the case.
The decision comes as the former deputy commerce minister Banyin Tangpakorn reported to the Crime Suppression Division yesterday to give additional statements, denying suggestions he was responsible for Chuwong's death.
Mr Banyin was 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.
Chuwong's family had asked police to replace the lead investigator, Pol Col Thaweerach Srithawachpong, who is deputy chief of the Metropolitan Police Bureau's Division 4.
They argued Pol Col Thaweerach was close friends with Pol Lt Col Banyin. The senior police officer belonged to the same class of police alumni as Pol Lt Col Banyin.
City police chief Pol Lt Gen Sriwara Rangsipramnakul said he found the reason cited by the family lacked sufficient weight to justify a change.
Pol Lt Gen Sriwara said every member of the investigation team was doing his best to be fair to all sides involved.
At the moment no possible motive has been ruled out and the cause of Chuwong's death has not been formally established.
Earlier, the autopsy result showed Chuwong had died from a brain haemorrhage and a swollen brain caused by his head hitting something hard. There were also deep bruises at the back of his head.
The forensic findings revealed no sign of a struggle prior to his death in the car crash, according to a police source.
Chuwong's family said they suspected irregularities in the businessman's death and in the transfers of substantial amounts of shares shortly before Chuwong's s death, to two women with whom he had affairs.
They have also given statements to investigators working on the case and deny any wrongdoing.
Pol Lt Gen Sriwara said yesterday the CSD and officers from other units working on the case will meet next week to review key evidence.
Meanwhile, Pol Lt Col Banyin spoke to senior police, including assistant police chief Prawut Thawornsiri and Central Investigation Police Bureau commissioner Thitirat Nongharnpitak at the CSD headquarters yesterday.
Pol Lt Col Banyin told reporters who gathered at the CSD that he was no murderer although some people have claimed he might be involved in Chuwong's death.
He had no conflict with Chuwong's family although he said a senior judge was advising the family to file a complaint with police to have the businessman's inheritance frozen so his mistresses cannot lay claim to the assets.