Bathinda, June 27 -- Four weeks after five migrant workers were killed and 27 others sustained injuries due to a blast at an illegal cracker factory at a Muktsar village, the cause of the explosion is still unknown as forensic experts have not submitted the analysis report. Investigators said on Thursday that a resident of Shamli in Uttar Pradesh, Nikunj Goyal, has been identified as the main supplier of the raw material used in the cracker production unit located at Fatuhiwala village. They said that as Nikunj is evading arrest, it is not known how he procured a huge volume of explosives and other material used in producing firecrackers. Muktsar superintendent of police (investigation), Manmeet Singh Dhillon, said that Nikunj supplied the material through a Karnal-based middleman, Prashant Goyal. Dhillon, who is heading a special investigation team (SIT) to probe the matter, said Nikunj has been nominated in the crime and coordinated efforts are on to arrest him. He said that they are awaiting a forensic report to ascertain the cause of the fatal accident. "Prashant hails from Assandh in Karnal, and he provided the explosive materials used for cracker production in Muktsar. Factory owners Tarsem Singh and his son, Navraj Singh, had tied up with Prashant to get raw material to start a fireworks factory without obtaining authorisation from the district administration. Besides these three, labour contractor Raj Kumar has already been arrested," said Dhillon. Police officials said that the fatal mishap could have been caused by a short circuit in the electrical supply at the unit or human error. "When the explosion occurred on May 30 at 2 am, rain and thunderstorms were reported in the area. There is also a chance that climatic conditions played a role in the explosion at the highly inflammable work station, which was built without safety arrangements," said an official....