CHENGDU, May 13 -- Local government sources said on Tuesday that an arson suspect in a bus fire was killed in the incident on Monday in Yibin in southwest China's Sichuan Province.

Yu Yuehai, 51, was believed to have set fire to the bus, killing himself and injuring many others, according to the government of Yibin City.

An initial investigation showed that Yu used to be a middle school teacher with Neijiang No. 7 Middle School, according to the press office of Shizhong District, Neijiang City.

He quit his job at the school in October 2004. His motive for the arson is still under investigation.

The bus caught fire around 4:50 p.m. on Monday when it was passing along Nanmen Bridge, said Hu Jingwen, a 12-year-old girl who was sitting in the last row of the vehicle.

Hu said she smelled gasoline before fire suddenly broke out at the back door of the bus. She managed to escape from the back window together with two of her classmates.

Altogether 77 people have been hospitalized, including three who were seriously injured and nine in critical condition.

Around 50 passengers were on the bus and most of them escaped through the front door, Hu said.

Further investigation is under way.