A university student who allegedly stabbed to death a young mother he had injured in a car accident has been arrested, police said.

Yao Jiaxin, a 21-year-old student at the Xi'an Conservatory of Music in Xi'an, capital of Shaanxi province, knocked down cyclist Zhang Miao while driving his Chevrolet Cruze at around 11 pm on Oct 20, when he was rushing to meet his girlfriend.

When he saw Zhang staring at his number plate, Yao is alleged to have taken out a knife and stabbed Zhang eight times until she was dead.

In a hurry to flee the scene, Yao allegedly injured two other passers-by, a man and a woman, according to police.

Yao was captured by police on Oct 22 and was detained on suspicion of murder the following day. On Nov 25, the local prosecutor's office issued an arrest warrant, police told a news conference on Monday.

Police said Zhang, 26, the mother of a 2-year-old boy, suffered only slight injuries in the traffic accident, including a fractured left leg.

But Yao allegedly admitted to police that he killed the victim simply because he feared the rural woman "would be hard to deal with".

Zhang's son often cried in his sleep and demanded to see his mother, said Zhang's husband, Wang Hui.

Wang said he would do all he could to ensure justice for the killer. But he feared Yao would be let off lightly. "I heard his parents are rich. How else could a student afford a car?"

Xu Tao, a Xi'an-based lawyer who offered the family free legal counseling, said Yao could face the death penalty if convicted of murder. The most lenient penalty, however, could be a 10-year jail term, if a murder charge was rejected.

Neither of Yao's parents was available for an interview on Tuesday. A neighbor said they had not been seen near their central Xi'an apartment since the incident.

A neighbor, who spoke on condition of anonymity, said Yao's father worked at a State-owned company in Xi'an before starting his own business.

The neighbor described Yao as a "talented young man".

Yao's teacher and classmates said he was a good student, but never talked much.

The tragic incident has sparked a new public furor over moral standards among the children of China's privileged classes, after police gave details of the accident at a press conference on Monday.

Many people speculated that Yao's parents might use their connections to bribe the authorities into letting him off with a lighter offence.

"It could be just the same old story of the rich and powerful doing whatever they want and never feeling guilty about it," said a netizen from Hebei province, where a similar outrage occurred.

A drunk 22-year-old driver gained nationwide notoriety by shouting "Sue me if you dare, my father is Li Gang" after hitting two students, killing one and injuring the other, on the campus of Hebei University in mid-October.

Li Gang was deputy chief of the public security bureau in Baoding city's Beishi district, where the university is located.

"My father is Li Gang" became infamous as a catch phrase, which netizens worked into jokes and doggerels to vent their fury over the vicious words and behavior of the children of power and wealth.

The driver, Li Qiming, has been charged with fleeing the scene of an accident, but the case has yet to go to court.

The widespread attention to the two cases reflected a public demand for justice and fairness, as well as worries over a "retreat of morality" amid China's economic boom, said a sociologist in Xi'an.

"Yao's extreme selfishness and apathy should be taken as an alarm for Chinese society, particularly for those who enjoy material abundance," said Shi Ying, deputy president of Shaanxi Provincial Academy of Social Sciences.

Shi warned that parents, teachers and the whole of society should reconsider the value systems they were helping the younger generation to cultivate.