Riders scan Ofo bikes in Xi'an, Shaanxi province. [File photo/China Daily]

The boy, whose name has not been revealed, was reportedly 12 or 13 years old. Witnesses said he and other boys were riding yellow bicycles at high speed and practicing drifting on a steep road in Zhengzhou, Henan province, when the accident happened on Sunday. The bicycles are run by Ofo.

Though the accident is under investigation, some said the boys illegally used the bicycles after cracking the password of the mechanical locks on the bicycles.

Users of Ofo bikes first need to pay via their mobile phones before they are sent the password that unlocks the bicycle.

Many primary students in Zhengzhou, however, showed that they can unlock the Ofo bicycles without the password, with one student unlocking four bicycles out of the 10 locked ones, according to the report.

According to law, those under 12 are not allowed to ride bicycles on roads. As Ofo's mechanical lock has long been criticized for its lax features, many question who should be held responsible for the safety of juveniles who illegally use the bicycles.

"I think the parents should be held responsible," said Liu Ming, a resident of Zhengzhou. He said he once saw his 9-year-old son riding the yellow bicycle and warned him.

Another resident, surnamed Wu, agreed on the importance of guardian's role but suggested that Ofo should change its mechanical locks into safer ones. Shared bicycles on other platforms use smart locks, which are hard to illegally break.

An Ofo employee said the company has launched bicycles with smart locks in Beijing and will introduce the new version in other regions of the country in the future.

If somebody dies due to quality defects or poor management of the shared bicycle, the company should take the responsibility, said lawyer Zhang Shaochun.

But if the minor cracked the password then the juvenile and the guardian should take the main responsibility, Zhang added.