Tawatchai Anukul, a former official of the Phang-Nga Provincial Land Department, was found dead inside a detention room at the Department of Special Investigation on Tuesday.
His brother, Chainarong Anukul, went to receive the autopsy result at the Police General Hospital at noon Wednesday.
Chainarong said the result showed that Tawatchai died of suffocation but he also had ruptured liver and bleeding inside his abdomen in a way that he was hit hard by a certain blunt object.
Chainarong said the relatives did not had any question about his death.
Tawatchai has been arrested for allegedly illegally registering land deeds for about 1,000 plots in Phuket and Phang-Nga.