A local Trinamool Congress leader was gunned down on the railway tracks at Bandel station in West Bengal's Hooghly district Saturday, police said.
Trinamool Congress has called a 12-hour shutdown in Chinsurah on Sunday in protest against the incident.
Dilip Ram (40), the TMC leader who was a railway employee, was rushed to the nearby Chinsurah Imambara Hospital.
From there he was referred to a hospital in Kolkata, about 45 km away and he died on the way, said Akhilesh Chaturvedi, Commissioner of Chandernagore Police.
He was shot at when he was on his way to catch train to Naihati station, which is across the Hooghly river, to reach office, the officer said.
A case of murder has been lodged and investigation into the incident is on, he said.
TMC has alleged involvement of BJP in the killing.
Hooghly BJP MP Locket Chatterjee and the party's state president Dilip Ghosh denied it saying "cut-money" and faction fight in TMC were behind the killing.
Chinsurah TMC MLA Asit Mazumdar said Ram and wife Ritu were the main organisers of the party.
Ram's wife is the Bandel gram panchayat head.
Ram, he said, had received a number of threat calls since May 23, the day the results of the Lok Sabha polls were declared.
"The BJP which has won the Hooghly Lok Sabha seat is trying to create a Bhatpara-like situation here. It is often threatening and driving out our party leaders. We had informed the Chandernagore Police commissioner and Chinsurah inspector in-charge several times but no action was taken," Mazumdar alleged.
Dilip Ghosh on the other hand claimed that TMC was responsible for the incident.
Bhatpara, a TMC citadel for long and home to migrant jute factory labourers, has been witnessing frequent post-poll violence between BJP and TMC.
The fight has intensified ever since Arjun Singh crossed over from TMC to BJP and won the Barrackpore Lok Sabha seat, under which Bhatpara falls.
Two persons have also been killed there.