A Beijing teenager who murdered his grandmother in her sleep and severely wounded his grandfather was sentenced to 12 years' imprisonment yesterday. He had attacked his grandparents after they refused to give him money to surf the internet. Without identifying the 17-year-old, Xinhua said he had been convicted of murder. In the incident three months ago, the boy attacked his grandparents with a chopper as they slept. The grandmother, 65, bled to death, while the grandfather suffered serious injuries to his right cheek and right wrist. The boy then searched their home, finding 2 yuan (HK$1.90), and fled. He turned himself in to police several hours later. Passing sentence in Beijing's No2 Intermediate People's Court, Judge Liu Yun called the murder 'a grievous offence'. Judge Liu lamented that many young people had become obsessed, and lost their self-control, in the face of the internet's lure. 'The internet has given [us] much convenience, but it also brings with it many problems that deserve our deep reflection,' the judge said. Quoting from the court's verdict, Xinhua said the boy was given a relatively light sentence because he was a juvenile when he committed the crime and he had given himself up and co-operated with police. The mainland has the world's second-biggest online population, just behind the United States. The number of internet users has reached 68 million and is rising rapidly. Most are young, male and single, recent research shows. They spend an average of 13 hours online each week, 10 hours of which are spent playing games. Authorities see obsessive use of the internet as a widespread social problem. A recent advertising campaign sought to put teenagers off cybercafes, claiming they encouraged violence and debauchery, and posed threats to social stability.