PATNA, Jan. 23 -- An explosion rocked Siwan's Hussain Ganj block on Thursday, leaving one person dead and three of his family members grievously injured, police said. The blast triggered panic in the area. The deceased, Mohammad Murtuza Mansoori (50), and his family were inside their house in Bargam village when the explosion occurred. Preliminary investigation suggested that illegal firecrackers were being manufactured at the residence, and the blast happened when containers packed with firecrackers caught fire. Police said the powerful explosion blew off the asbestos-fitted roof of Mansoori's house and flung his charred body several feet outside. The incident took place on the day chief minister Nitish Kumar was in Hussain Ganj for his Samriddhi Yatra. However, the site of the blast was around 7 kms away from the venue of the CM's programme....