A prisoner who died in a Samut Prakan prison recently was assaulted by fellow inmates who disguised his killing as an accident, a Finance Ministry inquiry concluded yesterday.

Wichai Khongsombat was beaten up by a group of 12 inmates in his cell on the night of April 15, said inspector-general Phokephibool Potranant. Wichai was found dead the next morning.

Tempers reportedly flared in the cell when Wichai, temporarily detained for drunk driving, stepped on sleeping cellmates. His 12 attackers then overpowered him and tied his wrists behind his back, while the 60 or so remaining prisoners in the cell looked on.

The 12 have been questioned by Khlong Dan police but not yet charged with any offence. The ministry set up the inquiry after Wichai's wife made complaints to the media.