A 13-year-old computer games enthusiast is facing charges of attempted murder after police said that they had thwarted a plan to shoot dead his teachers for giving him poor marks.

The boy, named only as Bastien, was arrested in Beauvais, 60 miles (96km) north of Paris, on Tuesday morning, hours after leaving his home in the nearby village of Allonne armed with his father’s shotgun and cartridges.

His parents were said to have been suspicious about his behaviour, including his unusually early 7am departure to Saint Esprit college, his Catholic private secondary school. They called police after finding a note on his blog saying: “This is my last muzik and certainly the last because Tuesday, November 17, 2009, will be the last day of my life. Sorry to leave you . . .”

Prosecutors believe that France narrowly escaped a school massacre of the type suffered so often in the US and, recently, in Germany and Finland. Police rushed to the 2,000-pupil school and sealed it off after searching it and failing to find Bastien. Pupils were told to sit on the floor away from doors and windows in case he was hiding in the building. Bastien’s father, a manager at an electrical company, later found him in a nearby internet café.

The boy told police that he had turned away from the school after seeing them blocking the gate. He had thrown the gun and ammunition into a field.

“He left his home with a loaded shotgun and 25 cartridges,” said Raymond Yeddou, a senior state official in Beauvais. “He went in the direction of the school where, according to his statement, he intended to kill all his teachers.”

James Juan, the local prosecutor, said that the boy had “wanted to attack his teachers because they found fault with him even though he had done nothing wrong”. Friends said that Bastien — usually near the top of his class at the highly competitive school — was upset that his teachers had recently given him middling marks.

The school denied that it had put any special pressure on him. Dominique Moutin, the headmaster, said: “I never had any problem with this pupil. I never had any idea that he could have such negative and dangerous ideas. But you never know.”

The incident again raised the question of the influence of violent online games. A boy who described himself as Bastien’s best friend said: “He always wanted to go into the army. He loved battles. He was passionate about history, warriors. He played video games up to one or two in the morning. I didn’t think that he would be capable of something like this. I don’t think he wanted to harm anyone.”

Bastien was said by friends to have been devoted to World of Warcraft, the hugely popular online game in which the player takes the role of a fantasy warrior from the Middle Ages. Christian Sadowski, the Mayor of Allonne, said that he knew the family well and that the boy was a fan of computer games. “Many young people end up finding it difficult to tell the difference between dream and reality,” he told The Times.

Bastien is likely to be charged in court today with attempted murder. Police said that he was in good health and did not appear depressed. He would face a maximum 20-year prison term if found guilty.

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