The national police chief has ordered a full investigation into the 27-hour siege at a house in Bangkok's Sai Mai district, where a mentally disturbed police officer fired his weapon more than 50 times before being shot by a Swat team.

The family of Pol Lt Col Kittikarn Saengbun, who later died in hospital from injuries sustained during the police raid on his house, has also filed a letter requesting an investigation of the siege last Wednesday.

On Monday, the family's lawyer said that the parents of the late policeman want clarification about the events that eventually led to him being fatally wounded at the end of the 27-hour, March 14-15 siege.

Pol Lt Col Kittikarn, 51, was an inspector attached to the Special Branch Bureau. He was shot and wounded by police commandos at noon on March 15.

Reports said that he died in hospital later that day.

However, the late policeman's family believe that police commandos might have used unnecessary firepower.

According to crime scene investigators, there were bullet holes in the back wall next to the window Pol Lt Col Kittikarn had been seen at and more all over the house.

The family has speculated that there was more gunfire than previously thought.

The lawyer said the family had asked police to wait until Pol Lt Col Kittikarn's parents arrived at the scene before storming the house.