A case of "unnatural death" has been filed and the body sent for autopsy, police said.
A BJP worker was on Friday found hanging from a tree in West Midnapore's Dantan area, fuelling suspicions that he was killed over political rivalry.
The man has been identified as Barsha Hansda.
Barsha Hansda, 44, was found hanging in the jungles of Santoshpur in Dantan area of West Midnapore - where the ruling Trinamool Congress and the BJP have been at each other's throats over the past one year.
A case of "unnatural death" has been filed and the body sent for autopsy, police said.
The BJP alleged that Barsha Hansda was murdered by Trinamool Congress supporters, a charge denied by the Mamata Banerjee-led party.
BJP national general secretary Kailash Vijayvargiya said the TMC was trying to establish a reign of terror in the state.
"The TMC is trying to terrorize BJP workers by establishing a reign of terror in the state. An active and popular BJP activist was brutally murdered by TMC goons. He was the only earning member of his family," Mr Vijayvargiya said.
Rejecting the allegations as "baseless", Trinamool West Midnapore district president Ajit Maity said the death was a result of internal rivalry within the BJP.
The Jangalmahal belt in Bengal, comprising West Midnapore, Purulia, Bankura and Jhargram districts, had been witnessing frequent clashes between the TMC and BJP workers since 2018 panchayat elections.
Three BJP workers -- Jagannath Tudu, Trilochan Mahato, Dulal Kumar -- were found hanging in separate incidents in Purulia last year, causing a huge political furore in Bengal.