A policeman was injured when an improvised explosive device (IED), suspected to have been planted by Maoists, exploded while he was trying to defuse it in Chhattisgarh's Bijapur district on Thursday, police said. This is the third such incident in Bijapur district in the last 22 days. The latest incident took place near Bangapal village under Nelasnar police station limits when a police team was out on area domination operation, an official said.