Criminals exploded bombs at a house Friday night after the housemaster refused to pay the amount demanded by them. According to police, a local gang demanded Tk 3 lakh from Sona Mia, a medicine trader a few days ago at Arpara village in Gangni upazila of Meherpur. Sona is too poor to pay the toll but the gang threatened him with dire consequences. On Friday night, the gang stormed into his house and blasted several bombs. None was injured in the incident. A case was filed with Gangni police station yesterday.