Govind Pansare, known for his rationalist views, was shot dead in Kolhapur on February 20, 2015.
The Kolhapur police in Maharashtra today took the custody of Sanatan Sanstha member Virendra Tawde, earlier arrested by CBI in Narendra Dabholkar murder case.
Kolhapur police obtained his custody in connection with the murder of CPI leader and rationalist Govind Pansare.
CBI had arrested Mr Tawde from Panvel in June, alleging that he was involved in the Dabholkar murder "conspiracy".
A police officer said here Mr Tawde had worked as an organiser for the conservative Hindu outfit Sanatan Sanstha in Kolhapur for some time, and therefore he came under the scanner of state police SIT probing the Pansare murder case.
The special CBI court in Pune had earlier allowed Kolhapur police to take his custody whenever needed. Mr Tawde is lodged in Yerawada jail near Pune.
Kolhapur police has already arrested Sameer Gaikwad, another member of Sanatan Sanstha, in the Pansare murder case.
While Dabholkar, a noted anti-superstition activist, was murdered in Pune on August 20, 2013, Govind Pansare, known for his rationalist views, was shot dead in Kolhapur on February 20, 2015. His wife too was injured in the attack.