Anwar Bhatkal drove auto-rickshaws and mini-trucks in Bhatkal before moving to Kuwait about eight years ago.
Akhtar and Waqas, along with others, Mohd Maroof, Wakar Azhar and Mohd Saqib Ansari, were arrested by the special cell in March.
The STF team of the Kolkata police arrested Hossain, a Bangladeshi national, from a railway station in central Kolkata.
The IP address of Nimbuzz chat, NIA claims, was traced to Pakistan Telecom Company Ltd.
Hossain was said to be a key operative in the terror group.
Hussain, a resident of Mirpur in Bangladesh, is suspected to be one of the main conduits of IM leaders in India.
An NIA team may also visit Nepal to help their counterparts collect evidence.
Waqas, 24, was shown as having been arrested in Ajmer on March 23, 2013, and accused of involvement in the bombings in Mumbai, Pune and Hyderabad.
Bhatkal was a key conspirator of the Mumbai triple blasts case in July’13.
The IB said the move was bound to increase terrorism and infiltration attempts along the Pakistan border.
Either the Sangh Parivar dilutes its demands from Sharif government. Or Sharif pulls off the impossible. Neither is feasible
An Interpol Red Corner notice was issued against him to secure his provisional arrest in Sharjah.
The UPA government has much to be ashamed of in its record on terror investigations.
Nothing was found against him.
ATS is currently interrogating Ashraf, who was remanded to 10 days police custody by a local court.