Nellore (AP): A mystery fire broke out in a sleeper class coach of Chennai-bound Tamil Nadu Express early this morning, killing 32 passengers and injuring 25 others in one of worst mishaps in the region which Railway Minister Mukul Roy suggested could be due to sabotage. It was an inferno on wheels as the superfast express train from Delhi to Chennai was travelling at a speed of over 100 km per hour when the tragedy struck the train. (PTI)