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The Bawana coaching centre owner Touqir, and the two private school teachers Rishab and Rohit, have been accused of leaking the Class 12 Economics paper an-hour-and-a-half before the exam was to start on March 26.
The police said the two teachers opened the question paper at 8:15 am and filled it; the exam was scheduled to start at 9:45 am. The two then took photos of the leaked paper and sent it to the coaching centre owner, who forwarded it to his students, the police said.
The identity of the Class 10 "whistleblower", who emailed CBSE chairperson Anita Karwal on the night before the Class 10 Math paper on March 28, has been withheld by the police. The mail contained 12 images of the handwritten Mathematics paper allegedly leaked on WhatsApp.
The police said the Class 10 boy received the paper on WhatsApp, following which he used his father's email ID to send the mail to Ms Karwal. The student and his father are being questioned, a police officer said.
Crime branch officers have fanned out across the National Capital Region or NCR to raid five locations -- apart from Delhi -- in connection with the CBSE paper leak.
The police say in all some 53 students and nine teachers have been questioned so far. Six WhatsApp groups that were involved in sharing the papers are also being looked into. In Jharkhand's Chatra district, 12 people, including Class 10 and 11 students, have been questioned for allegedly accessing the leaked question papers, the police said.
After the math and economics paper leaks, the CBSE has cautioned against fake paper leak messages being circulated on social media. A Political Science question paper found on YouTube has been verified as an "earlier year's question paper", the board said in a statement. "A fake question paper of Class 12 Hindi (Elective) is being circulated on social media," the CBSE said in the statement.
Despite getting the email from the Class 10 student -- one of many such warnings the CBSE had received -- the education body on March 28 filed a second complaint with the police 90 minutes after the Mathematics exam. Union Education Secretary Anil Swarup has said there was not enough time to cancel the Class 10 Mathematics exam.
The police had also filed a separate case on March 27 to probe the leak of the Class 12 Economics paper, following a complaint by the regional director of the CBSE. The Class 12 economics exam was held on March 26.
The CBSE re-exam will be held only for students based in Delhi and Haryana only if the investigation points to a "large-scale leak", Union Human Resource Development Minister Prakash Javadekar had said on Friday.