The Department of Special Investigation (DSI) has accused the Thung Song Hong police of filing incomplete investigation reports into the death of a former land official accused of fraud, forcing a new probe to confirm the cause of death, according to a Justice Ministry source.
The Criminal Court ruled last Friday that the land official, Thawatchai Anukul, died of suffocation and a ruptured liver after he was struck by a blunt object on Aug 29 last year while in DSI custody.
But the court did not indicate who was responsible for causing his death, while mystery also surrounds the exact manner in which he died, the source said.
The DSI said earlier the 66-year-old was was found unconscious but still alive in a detention room after he was suspected of attempting to hang himself from a door hinge. He is believed to have made a noose using his socks.
He was rushed to Mongkutwattana General Hospital on Chaeng Wattana Road, where he was later pronounced dead, the DSI said.
The DSI asked a public university to help clarify what caused the man's death but the "Thung Song Hong police did not present that information to the court", the source said.
The DSI also took opinions from doctors at the Police General Hospital and presented these as evidence in the case.
Investigators must now piece together information from various sources to try and unravel the mystery of Thawatchai's death, the source said.
These include inquest results by forensic experts from three Thai universities -- Chulalongkorn, Siriraj and Ramathibodi -- an X-ray scan of the corpse, accounts from staff at the hospital, and an animation demonstration whether he could have used the socks to hang himself as claimed by the DSI.
At the time, Thawatchai was being held by the DSI after it received a complaint from the National Park, Wildlife and Plant Conservation Department accusing the former Phangnga land official of involvement in a land encroachment case at Sirinat National Park in Phuket.
He had been on the run since the National Anti-Corruption Commission implicated him in a number of crimes in 2003 relating to abuse of power, the DSI said.
He was accused of dereliction of duty for issuing land deeds for Layan beach in Phuket's Thalang district. A second charge saw him accused of illegally issuing land documents for 500 rai of land in Hat Thai Mueang-Khao Lampi National Park in Phangnga.
Refusing to accept the suicide claim, his brother Chainarong has vowed to take legal action against anyone involved in Thawatchai's death.
Pol Lt Col Suban Athiset, deputy chief of Thung Song Hong police, said investigators will re-examine the case once they receive a request from prosecutors.
DSI chief Paisit Wongmuang said his agency will cooperate by allowing the police to interrogate the DSI officials who oversaw his detention.