The police said Kartak had competed his BCom and BEd and taught at various schools before starting his own classes for students of Classes 8 to 10. He was doing well financially and had around 250 students attending his classes.
He has a house at Parsi Colony in Dadar as well as a flat at Napean Sea Road. "We have checked his mobile phone and classes but didn't find any pornographic material," said Yadav.
Parents of the seven children had approached the Shivaji Park police on Sunday alleging that Kartak had been sodomising their children over the past few months.
The boys told the police they were afraid of telling anyone and weren't even aware that there were others involved. "Kartak would allegedly sodomise a boy on the excuse of making him stay back for extra classes. When the victims realised what he was doing, they decided to get together and tell their parents."
Kartak was arrested on charges of unnatural sex. He was produced before the local court on Monday that remanded him to police custody till December 30.
The police have also sent the victims for medical tests to Nagpada police hospital and are waiting for the results.