Calcutta: Pressure mounted for the arrest of the principal of the GD Birla Centre for Education after the father of the four-year-old tormented child lodged a formal complaint with police and the state child protection watchdog spoke to the police commissioner.

Tempers ran high after the content of a letter attributed to principal Sharmila Nath and addressed to the child's father created an impression that it was a perfunctory effort. That the letter was handed over to a shop downstairs, and not in person to the grieving parents, did little to limit the damage.

The letter, the veracity of which could not be corroborated with the principal, empathised with the family and expressed concern for the child but described their trauma as "your present predicament".

It signed off: "Do feel free to get in touch with the undersigned for any queries that you may have." 

The father of the child said: "Someone had left this letter last evening (Saturday) at a shop on the ground floor of the building where we stay and asked the shopkeeper to deliver it to me. I received it at 8pm."

He added: "I expected that someone from the school would come to my residence and speak to my daughter. That could have alleviated her pain and she could have understood there are good people in the school - nice people who will be around her if she ever goes back."

In the evening, the police drew up an FIR against the principal on the basis of the father's complaint that alleged she did not take any measure to prevent the sexual assault despite an earlier instance. The father accused her of trying to save the accused.

A section in the law to protect children from sexual offences that deals with failure to report an offence has been invoked. The charge carries a maximum punishment of one year in jail. The FIR also mentions IPC sections on criminal conspiracy, cheating and causing disappearance of evidence as well as false information to shield an offender.