An investigation by the Bihar government’s Economic Offences Unit into alleged irregularities in the National Eligibility-Cum-Entrance Test “clearly suggests a paper leak”, The Indian Express reported on Sunday.

The Union government had sought a report from the state agency, which took over the investigation after the arrest of 13 people, including four candidates who appeared in the medical entrance test.

The Economic Offences Unit, in its report to the Centre, stated that there was a “clear suggestion of a paper leak based on evidence so far, probable involvement of an inter-state gang, and suspected role of Bihar’s notorious solvers gang,” The Indian Express quoted unidentified sources as saying.

The agency said that a “solver gang” based in Bihar’s Nalanda district may have procured the question paper of the entrance exam from Jharkhand, solved it with the help of experts and then passed on the answers to two other accused persons – Nitish Kumar and Amit Anand.

The examination was held in 27 centres in the state on May 5. Later that day, the Patna Police received information of alleged irregularities in the medical entrance exam at multiple examination centres and a case was filed.

The Economic Offences Unit took over the investigation on May 11. The investigative team said that admit cards, along with post-dated cheques and certificates of several candidates, were seized from members of an “organised inter-state gang”.

Apart from the 13 persons arrested on May 5, six others were arrested by Bihar’s Economic Offences Unit from Jharkhand late on Friday. With this, 19 persons have been arrested in the case in Bihar.