The arrested accused, identified as Siam Hossain, originally hails from Burhanuddin, Bhola district in Bangladesh. Hossain had fled to Nepal following the murder of the victim Bangladesh MP.
The accused was intercepted in Bangaon of North 24 Parganas district near the India-Bangladesh border.
Earlier, one Jihad Hawladar was also arrested, an alleged Bangladeshi immigrant, in connection with the case. The main accused, Akhtaru Jaman Shaheen, remains at large. Interpol has been approached to assist in locating him.