A Chinese state media report says a fire on a double-decker bus that killed 41 people last month was caused by flammable chemicals that were being illegally transported on board.
Xinhua News Agency says investigators found that the chemicals directly caused the fire, which also injured six people. It did not say what the chemicals were.
Wednesday's Xinhua report cites investigators as saying passenger vehicles are prohibited from transporting flammable or explosive chemicals. It says nine suspects are in police custody.
The overloaded bus burst into flames on a central China highway on July 22. The sleeper coach had a 35-passenger limit but was carrying 47 people.