A Central Bureau of Investigation team probing alleged irregularities in the conduct of the University Grants Commission-National Eligibility Test was attacked in Bihar’s Nawada district on Saturday, PTI reported.

Four persons were arrested for the attack, the news agency reported.

The exam for the post of assistant professor in universities and colleges was conducted by the National Testing Agency on June 18. It was cancelled on June 19 after the Union education ministry said that the integrity of the examination “may have been compromised”.

On June 20, the Centre handed over the probe into the matter to the Central Bureau of Investigation. The agency has filed a first information report against unidentified persons for irregularities in the examination.

On Saturday, a team of the central agency went to Kasiadeeh village in Nawada district when a mob gathered around their vehicles and heckled the officers, PTI reported quoting unidentified officials.

“A CBI team reached Nawada on Saturday evening to investigate the UGC-NET paper leak case,” Station House Officer of Rajouli police station Rajesh Kumar told the Hindustan Times. “Without informing the local police, they [CBI team] reached the village where they were attacked by villagers who mistook them for fake officers. As we came to know about the incident, police reached the spot and pacified people.”

The central agency is investigating the matter on the basis of mobile numbers, an unidentified police official told the newspaper.

On June 20, Union education minister Dharmendra Pradhan had said that the question paper for the University Grants Commission-National Eligibility Test was circulated on the messaging platform Telegram before the examination.

“Fresh examination shall be conducted, for which information shall be shared separately,” the Centre had said on June 20.