The principal of a school in neighbouring Mumbra, from where SSC exam papers allegedly leaked and where the main accused was employed, is currently being interrogated in connection with the probe into the case, police said today. Police said they have observed several irregularities in the functioning of the school in which main accused Firoz Khan worked. Khan didnt have a proper appointment letter or other valid documentation but he still had access to exam papers. We are questioning the principal as the leak allegedly originated from the school, said a police official. The principal has told police that she along with Khan had access to the room in which the papers were stored, officials said. Amboli police, which is investigating the case, have so far arrested four persons in this connection. Eight students have been booked and are facing action under the Juvenile Justice (Care and Protection of Children) Act. A similar case which occurred in Saki Naka is also being probed to check if there are any links to the Amboli one, said officials. The leak of the SSC Board exam paper of History and Political Science (Part 1) was revealed on March 20 after the exam invigilator of a school in Andheri noticed some students constantly referring to their notes and mobile phones outside the exam hall. On checking the phones of these students, the invigilator found that the paper, scheduled for the day, had been leaked. On being alerted about the matter, Amboli police arrested three persons, including Khan, the same day. A case was registered under the Information Technology Act and Maharashtra University Act, officials said.