The CPI(M) district committee member Sattar Mollah and seven other party activists were later arrested in connection with the murder, police said.
Nazrul Mollah, a panchayat poll booth committee member of TMC, was called out from his residence by some people and shot at from point blank range, police said, adding he died on the spot.
The Trinamool alleged Mollah was an active party worker and he was killed to scare away the party supporters and voters in the area.
The third phase panchayat polls in West Bengal will take place on July 19.