Their burnt bodies were found at Namkhana in South 24 Parganas district, the police said.
"An incident of fire was reported. A man and his wife were burnt to death. Forensic experts have been called in," said police officer Tathagata Basu.
In a letter to the state election commissioner, a CPM leader said Debu Das had been threatened by Trinamool candidate Amit Mondol and his aides during the campaign for the Bengal panchayat election, which has seen widespread violence during voting on Monday.
The CPM has accused the local election officer of inaction against violence at polling booths.
Another person, Amrito Saha was seriously injured after being attacked allegedly by Trinamool supporters in Cooch Behar. He was undergoing a surgery at the Raiganj hospital when reports last came in.
As many as 20 people have been injured in poll-related violence in Cooch Behar. "A group of us had gone to cast our vote at a polling booth. We were attacked by TMC workers with lathis," an injured voter told news agency ANI.
The Trinamool, on the other hand, claimed that one of their workers, Anarul Mitra, was shot by BJP men in Cooch Behar's Dinhata late on Sunday night; he is in a critical condition.
Violence has also been reported from politically volatile Bhangar, where a media vehicle was set on fire.
Chief Minister Mamata Banerjee, on the eve of panchayat polls on Sunday, had appealed to people to stay calm and not believe in "fake videos". The Chief Minister told a local news channel, that her government will "play a strong role and not spare anyone found to be disturbing peace." She said her government has taken strict action against Arabul Islam, a Trinamool leader who is a murder accused because it was the right thing to do.
The counting for the panchayat polls will take place on May 17.