Four persons, including the Congress candidate for Malda’s Mothabari Assembly constituency, and an elected panchayat member of the ISF, were interrogated by the National Investigation Agency (NIA) on Sunday in connection with the detention of seven judicial officers by a mob at the Kaliachak-II block development office in Malda on April 1.

Sources said the quartet was summoned one after another to the NIA office in Murshidabad district for questioning.

Sayem Chowdhury aka Babu, the Congress candidate from Mothabari, was stopped during an election rally around 3pm on Sunday and directed to appear before the agency. Chowdhury complied and was questioned in connection with the April 1 hostage crisis that prompted the Supreme Court to order an NIA probe.

Around the same time, Golam Rabbani, a decorator by profession and an elected ISF member of the Mothabari gram panchayat, was picked up from his residence at Chak Pratappur village under Mothabari police station and taken to the NIA office for interrogation.

Two others linked to the Congress — Sahadat Hossain of Amritala and Asif Sheikh, a Chhatra Parishad leader and block president in Kaliachak-II under the Mothabari Assembly constituency — were also summoned.

The case pertains to an incident on April 1 when seven judicial officers, including three women, were allegedly prevented from leaving the Kaliachak-II BDO office after completing work related to “under adjudication” voters under the special intensive revision (SIR) of electoral rolls.

The officers were held for nearly seven-and-a-half hours as a large mob, protesting uncertainty over their enfranchisement, blocked roads leading to the office.

Around 8pm, the officers alerted the Election Commission of India and the Calcutta High Court. The matter was also conveyed to the Supreme Court. A large contingent of police and central forces later rescued them at 12.18am on April 2.

It was alleged that while the officers were being escorted to Malda town, one of the SUVs was attacked at Amritala.

The driver was assaulted, and an audio clip — purportedly of a judicial officer pleading for help — surfaced later, though its authenticity could not be independently verified.

Taking serious note of the incident, the Supreme Court ordered an NIA probe on April 2. The agency began its investigation after arriving in Malda on April 3.

So far, 41 persons, including ISF candidate Moulana Shahjahan Ali, have been arrested in connection with the case.