Shillong, June 12 (PTI) The police is preparing a report about yesterday's explosion of a grenade near the Assam Rifles Unit here. Police is preparing a report on the incident and would be submitted to the Gorkha Training Centre (GTC) authorities, ASP (crime) Vivek Syiem said. The 42-year-old rag-picker, Petros Nongdhar, had got hold of the grenade from near the firing range of the GTC at around 3 pm yesterday, police said. Apparently ignorant of the explosive, he tried to sell it off to a scrap dealer for about Rs 20 as per its weight but he could not get any takers. Later, after a few doses of booze he threw it in a drain in front of the main gate of an Assam Rifles unit at Madanriting where it exploded. Interestingly, for three hours, the rag-picker was carrying the grenade without the pin and it was the impact of it hitting some hard material in the drain that made it explode, the ASP said.