Police on Wednesday arrested two persons and detained four others for their alleged involvement in operating an illegal firecracker factory in Egra area of West Bengal's Purba Medinipur district, where nine people were killed in a blast, a senior officer said.
The duo was arrested for illegally storing gunpowder, he said.
A police team from Purba Medinipur district also visited neighbouring Odisha in search of the absconding factory owner.
“The arrests were made during search operations carried out at the locality late on Tuesday night,” the officer told PTI.
"The factory owner fled to neighbouring Odisha soon after the blast. We are trying to spot him on the basis of his mobile tower location. Hopefully, we will be able to nab him soon," he said.
The district police has lodged an FIR in connection with the explosion that took place on Tuesday in which nine people were killed and several others injured.
Teams from the CID, forensic department and bomb squad have also started their investigation into the blast.
Forensic experts collected samples from the now-collapsed house at Khadikul village, which housed the illegal firecracker unit, and its surroundings, he said.
The CID officers also spoke to the witnesses as well as with family members of those killed in the blast. A huge posse of local police has been deployed in the village near the Odisha border.
The condition of the four people injured in the explosion is stated to be "critical", one doctor of the hospital, where they are undergoing treatment, said.
"One woman is extremely critical and the condition of the other three can only be described as not out of danger," the doctor said.
Meanwhile, West Bengal Governor C V Ananda Bose strongly condemned the incident and prayed for the departed souls.
"It's a very unfortunate incident. This should not have happened. Everyone has to work together to bring peace in the state," Bose said.
Senior BJP leader Suvendu Adhikari also reached Khadikul village on Wednesday morning. He spoke to the locals and tried to take a look at the house where the factory was housed, from the terrace of a neighbouring building.
Adhikari, who hails from Purba Medinipur district, repeated his demand for an NIA probe into the explosion.
Chief Minister Mamata Banerjee had on Tuesday said though the CID has been entrusted with the task of probing the explosion, she has no objection if the NIA starts investigating the matter.
Earlier in the day, a section of agitating villagers of Khadikul, who had blocked police from entering the area, started demonstrating when a team of Trinamool Congress leaders led by Environment Minister Manas Ranjan Bhunia went there.
Bhunia, who was accompanied by TMC MP Dola Sen and MLA Saumen Mahapatra, met family members of the deceased and assured them that the state government would take care of their needs and arrest the culprits.
However, their stay was short-lived after a section of villagers questioned why the administration was a day late in reaching the village, and started shouting 'chor chor' (thief thief).
"We request the villagers to let the administration work and cooperate with it," Bhunia said.
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