HARBIN, May 13 -- Local police in northeast China's Heilongjiang Province have detained a man who allegedly caused a major fire disaster in the forested Greater Higgnan Mountains during the past May Day holiday with a cigarette butt.The man, identified as Dong Chunlin, who is a resident of Nenjiang County, was detained on Friday, according to information from the security bureau of the Daxing'anling Administrative Office of Heilongjiang Province.During interrogation, Dong, 51, confessed that on April 30, he smoked outside a cave dug into the mountains near Hannuohe Meadow, then carelessly threw away the burning butt into the nearby brushwood and went inside the cave to take some rest.Dong was awaken about an hour later, by the thick smoke of the forest fire, to find the conflagration was out of control.The fire, which broke out in the afternoon of April 30, ravaged 10,400 ha of land, including 10,317 ha grassland and 83 ha forest.The national headquarters for the prevention of forest fires sent about 10,000 fire-fighters, together with airplanes, to help extinguish the fire. The fire was put out five days later.Dong's case need further investigation, according to the police.