The father of a 10-year-old boy detained in Class IV of a reputable south Calcutta school for two years has filed an FIR accusing his class teacher of turning vindictive after being refused a laptop as bribe.

“I have text messages on my phone to prove that my son’s class teacher demanded a laptop,” said the father, who lodged the complaint with Shakespeare Sarani police station last Friday.

Police confirmed receiving the complaint, which also accuses the principal of the school of trying to force the boy’s parents to transfer him to another school. “The primary allegation is against the teacher but we will need to interrogate the school principal as well. We have started a case of extortion, which is a non-bailable offence, and criminal intimidation,” an officer said.

The principal of the school was unavailable for comment till late on Monday, prompting Metro to withhold the names of the complainant, the accused and the school.

According to the father, his son was allegedly first targeted in Class III with his then teacher branding him a below-average student who required counselling. “We immediately took him to a psychologist, who found him to be a perfectly normal boy,” said the father.

The boy, who lives near Tollygunge, made it to Class IV but the promotion allegedly brought with it more problems. “His new teacher appeared friendly but I smelt a rat when he started sending messages declaring how powerful he was. He finally sent an SMS asking, ‘Can you give me a laptop with Internet connection, I will be in constant touch with you and I can provide exam question papers’,” the father said.

The teacher allegedly began finding fault with the boy when his father refused to bite the bait. “Around November 2008, he wrote to me claiming that my son was writing rubbish in class and that he was worried about him being detained. Under pressure, I sent him a second-hand desktop but that did not satisfy him,” said the father.

The boy was then allegedly detained for two years in violation of an ICSE rule that prohibits schools from holding students back till Class IV.