Police in northwest China's Shaanxi Province are offering a cash reward for information leading to the conviction of a hit-and-run truck driver who killed three teenage girls and a boy.

The four cyclists, aged from 13 to 15, were on their way to school in the suburbs of Xi'an, the provincial capital, Tuesday when a heavy truck knocked them down on state highway No. 108 at around 6:05 a.m..

Another student, 15-year-old Zhang Tian, suffered serious pelvic injuries and was still under intensive care Thursday.

Police are offering a reward of up to 100,000 yuan (US$14,634) for information that could lead to the driver's conviction.

At least 100 policemen with Xi'an Public Security Bureau are investigating the case and looking for the killer truck, which a witness said was orange in color.

Wang Jianxu, a traffic police officer in the suburban Chang'an District, said the truck was likely to be a Chinese-made Dongfeng, judging from a fender board left at the scene.

Wang said the driver must be "sly and experienced", as the marks on the ground showed that after the accident, he bypassed a toll station on the truck road, where the only camera lens in the area was installed.

"The driver didn't brake or even slow down (after the accident)," said eyewitness 15-year-old Kai Ze.

The boy said he chased the truck for about 100 meters but was unable to read its number plate. "I saw clearly it was an orange truck," he said.

Villagers complained to Xinhua the area had no street lamps, but most students needed to leave home at 6 a.m. in order to arrive at school before 6:30 a.m. for the morning class.

"It's OK in summertime, but in winter, it's still pitch-dark," said a father on condition of anonymity.

(Xinhua News Agency February 12, 2009)