Since yesterday, 12 people, including Class 10 and 11 students, have been questioned in the CBSE leak case from Jharkhand's Chatra district, they said.
The examination board came under criticism after its Class 10 mathematics and Class 12 economics papers were leaked earlier this week.
On Friday, the police had detained six Class 10 students in the case.
A Class 11 student was detained from the Navodaya Vidyalala campus. According to police, he had hid chits containing answers of a leaked question paper in the school's bathroom. Two students are from Patna, they said.
The directors have been put under arrest, says police.
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