The CBI on Wednesday quizzed the principal of a private school in Jharkhand's Hazaribagh who is under the scanner in connection with the NEET-UG examination paper-leak case, officials said.

The federal agency quizzed Oasis School principal Ehsanul Haque, who was also the district coordinator of the National Testing Agency (NTA), they added.

The Economic Offences Unit (EOU) of the Bihar Police, which was probing the case earlier, had found burnt question papers of the NEET-UG during a raid at a hideout of the solver gang, the officials said.

In a statement, the EOU had said the leaked NEET-UG question paper was allegedly obtained from the Oasis School in Hazaribagh by the notorious Sanjeev Kumar alias Lutan Mukhiya gang.

It had said the investigators had matched a partially-burnt question paper found from the Patna safe house with the reference question paper provided by the NTA, confirming the leak's origin.

However, it could not clearly establish who was behind the alleged paper leak, the officials said.

In media interviews, Haque has maintained that the box carrying the question papers could not be opened because its digital lock, which was supposed to unlock automatically, had malfunctioned.

Following this, he contacted the NTA, which asked him to use a cutter to open the box.

The boxes carrying question papers have two locks -- a manual one that must be opened with a key and cutter and a digital lock that opens with a beep 45 minutes before the examination.

The CBI took the evidence collected by the investigators and held deliberations with the officers of the EOU.

The EOU has arrested 18 people in connection with the case. The CBI is likely to seek their remand.

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