Three people, including a woman, a police constable and an undertrial prisoner were killed and more than half a dozen injured in a bomb blast in a Bihar court Friday, police said.A district police officer said a crude bomb exploded within the premises of Ara civil court in Bhojpur district, about 60 km from the state capital.The injured were rushed to the local civil hospital for treatment.Security in the court premises was beefed up following the blast.Additional Director General of Police Gupteshwar Pandey told media here that the bomb that exploded was carried by a woman, one of the victims."Police have recovered a mobile phone near the mutilated body of the woman," Pandey said.According to an official at the chief minister's office, the union home ministry has sought a report about the incident from the state government.