The driver of the ill-fated Hyderabad-bound Volvo bus was overstressed and there were firecrackers inside the vehicle, according to findings of an investigation that probed two recent road mishaps in which 52 persons were killed.

The investigation has said that “the driver was overstressed. He could not find brake and was assigned on double duty,” Road Transport and Highways Minister Oscar Fernandes told PTI.

“There were firecrackers also in the Bangalore-Hyderabad bus,” he added.

In the first accident on October 30, 45 passengers were burnt alive, as the Volvo bus they were travelling from Bangalore to Hyderabad burst into flames after its fuel tank caught fire on hitting a culvert at Mahabubnagar in Andhra Pradesh.

The bus might have caught fire due to a spark and firecrackers might have exploded, the Minister said.

In the second incident on November 14, seven passengers were killed and 40 injured when a Mumbai-bound bus from Bangalore caught fire after hitting a road median at Haveri in Karnataka.

The causes behind the second accident are being ascertained, Mr. Fernandes said.

Meanwhile, a preliminary report by Accident Data Analysis Centre of National Automotive Testing and R&D Infrastructure Project has said that the buses had wooden flooring and inflammable seats and the speed limit was also high, according to sources.