Kolkata, Feb 16 (IANS): West Bengal's ruling Trinamool Congress Monday retained the Bongaon Lok Sabha and Krishnaganj assembly seats where by-polls were held last week.

The BJP finished second in Krishnaganj, pushing the CPI-M, which heads the opposition Left Front to the third spot. In Bongaon, the CPI-M finished second while the Bharatiya Janata Party (BJP) took the third spot.

The Congress came fourth in both the seats.

In Bongaon, Trinamool candidate Mamatabala Thakur trounced her nearest rival Subrata Thakur of the BJP by over 2.11 lakh votes. The Trinamool nominee led in all seven assembly segments of the primarily rural constituency, comprising parts of North 24 Parganas and Nadia districts.

Communist Party of India (Marxist) (CPI-M) nominee and former state minister Debesh Das, who had finished runner up in the 2014 Lok Sabha election, was at the third position in the initial rounds, but made up midway through the counting to take the second position. Congress candidate Kuntal Mondal forfeited his deposit.

The by-poll was necessitated after the death of Trinamool MP Kapil Krishna Thakur. Mamatabala is his widow and Subrata his nephew.

In Krishnaganj in Nadia district, Trinamool candidate Satyajit Biswas won by over 37,000 votes against his closest rival Manabendra Roy of the BJP.

The Trinamool retained its vote share of last year's Lok Sabha polls from the assembly segment while the BJP's vote almost doubled.

CPI-M's Apurba Biswas secured far lesser votes this time as compared to last year.

Congress candidate Nityagopal Mondal lost his deposit.

The seat fell vacant due to the death of Trinamool lawmaker Sushil Biswas.

Over 80 percent voters cast their votes Feb 13 in the two seats, reserved for scheduled caste candidates.