BJP leader Mukul Roy was among four people booked on Sunday in connection with the killing of Trinamool Congress (TMC) MLA Satyajit Biswas in West Bengal's Nadia district, police said. Roy, a former TMC general secretary who joined the BJP last year following differences with party supremo Mamata Banerjee, denied the allegation, saying the decision to name him in the FIR was "politically motivated". A West Bengal Police officer told PTI that two of the four people named in the FIR have been arrested on Sunday. The two arrested persons - Kartik Mondal and Sujit Mondal - were remanded in 14-days' police custody by the acting additional chief judicial magistrate, Ranaghat court. Amid allegations that there was no security cover despite the MLA and a minister being present at the Saraswati Puja celebrations venue where the incident occurred on Saturday, the officer in-charge of local Hanskhali police station and the personal security officer of Biswas were suspended. A departmental inquiry has also been initiated against the OC and the PSO, who was reportedly on leave on Saturday, police said. Speaking on the progress in the investigation, the police officer said, "So far, we have arrested two persons and detained three others. A country-made revolver used to shoot the MLA has also been recovered. "As per our primary findings, it seems that the victim was shot at from behind and the act was the result of a well-planned plot," he said. Asked about the chances of the assailants fleeing to the neighbouring country, the officer said the state police has been put on a high alert. "Nadia shares border with Bangladesh and there could be a possibility of them (assailants) trying to escape to the neighbouring country. Police have been put on high alert to check the movements along the border," he said. The country-made revolver was recovered from a ground near the place of the incident. The Krishnaganj MLA was shot from a point blank range by unidentified assailants Saturday evening inside a Saraswati puja marquee at Phoolbari village, about 15 km from the Bangladesh border. He was immediately taken to a local hospital where doctors announced him "brought dead". His body was brought home from the hospital Sunday morning for last rites, amid a blame-game between the ruling party and opposition BJP leaders over who was responsible for the death. A large crowd gathered to pay last respects to the deceased MLA at his residence, a few metres away from the Saraswati Puja marquee where he was shot at. Roy, one of the four persons against whom the FIR has been lodged in connection with the killing of Biswas, said the legislator's killing could be a result of infighting within the TMC. "Naming me in the FIR is absolutely a politically motivated move. I am sorry about Satyajit's death, but the manner in which they (TMC leaders) are trying to hold the BJP responsible is nothing but a dirty conspiracy," Roy, a former Railway minister, told PTI. TMC secretary general Partha Chatterjee, however, alleged that goons who killed Biswas belonged to the saffron party. Along with party's Nadia district observer Anubrata Mondal, who asserted that the "none of the perpetrators will be spared", Chatterjee accompanied the MLA's hearse to his residence from the hospital. Stating that the chief minister was shocked to learn about the incident, Chatterjee said, "Those who think that they will gain by eliminating Satyajit, are living in a fool's paradise." Chief Minister Mamata Banerjee spoke to the family members of the deceased MLA and assured them all assistance, TMC sources said. Chatterjee, also the state Education minister, alleged attempts are being made to create a divide among the Hindus and also within the Matua community. Biswas belonged to the Matua community - deemed vital as a support base in Bengal. The Matuas are a scheduled caste community with a sizeable population in some districts of the state, including North 24 Parganas and Nadia. Urban Development minister Firhad Hakim alleged that "BJP is importing the politics of violence and murder in West Bengal from Gujarat. "They think that they will win the seat if they eliminate him (Biswas)," he said. Hakim squarely blamed the BJP for the killing of Biswas. "The prime minister came to woo the Matua community in Thakurnagar last week. Now the local BJP leaders are resorting to criminal activities to gain political turf," he alleged. TMC Nadia district president Gouri Shankar Datta also accused Roy of being involved in the incident. "Roy is the mastermind behind this killing. We demand his immediate arrest," Datta told PTI. Denying allegations of the BJP's involvement, the party's state president Dilip Ghosh demanded a CBI investigation into the killing. An independent probe will reveal the truth, he said. Ghosh echoed Roy's sentiments saying Biswas was a victim of internal feud within the ruling party. "If an MLA gets killed like this, how can the common man feel safe?" he asked. CPI(M) state secretary Surjyakanta Mishra said that this incident shows that nobody is safe under the TMC rule. He demanded an impartial probe to reveal the truth.