Sources said investigating officers found an empty packet of surgical hand gloves from the flat, indicating the possibility of an attempt by the 'attackers' to leave no fingerprints.

Moreover, two persons named Mustafizur and Faisal, who have been arrested by Bangladesh Police, had reached Kolkata 10 days before Azim reached the city for 'medical treatment'.

The two reached Kolkata on 2 May and stayed in a hotel on Mirza Ghalib Street in central Kolkata till 13 May. The Bangladeshi MP had reached the city on 12 May and was missing since 14 May.

The CID suspects that Mustafizur and Faisal had reached Kolkata well in advance to plan to 'eliminate' Azim.

The CID has collected CCTV footage from the hotel where Mustafizur and Faisal stayed, along with details related to their booking.

Sources said the hotel staff told the investigating officers that DU had made all the payments in cash.

Before going missing, Azim, a three-time MP from Bangladesh, was staying at the residence of his friend Gopal Biswas in Baranagar.

On 14 May he left, telling Biswas that he would return the same day. However, he has not been traceable since then and his mobile phone is also switched off.