A Government inquiry headed by former Supreme court judge UC Banerjee to investigate the Godhra Train Fire concluded that the fire was not a work of sabotage and it spread from the inside.
For details read:
http://news.bbc.co.uk/2/hi/south_asia/4180885.stm

I can even quote the human rights watch reported that has cast suspicions over the claim that the fire was the work of a Muslim mob.