Maoists exploded an improvised explosive device (IED) in Chhattisgarh's Dantewada district on Tuesday, killing five policemen who were escorting BJP MLA Bhima Mandavi who too was killed, authorities said.The deadly explosion took place around 5.30 p.m. in Kuakonda area in Dantewada. "All the killed security personnel are from District Reserve Group," said an official. The District Reserve Group is a locally raised force vested with battling Maoists. Mandavi was the lone Bharatiya Janata Party MLA from Bastar region which accounts for 12 Assembly seats. The Maoist attack came two days before the start of the Lok Sabha polls.