Tear gas may have started a fire at this cabin, where a fugitive ex-cop is thought to have been cornered. The building burned down during a shootout between police and a man believed to be Christopher Dorner. The 33-year-old is wanted for a killing spree targeting police and their families. Remains found at the cabin are thought to be Dorner's - although no formal identification has been made. Police are investigating the cause of the blaze. SOUNDBITE: (English) SAN BERNARDINO COUNTY SHERIFF JOHN MCMAHON, SAYING: "I can tell you that it was not on purpose, we did not intentionally burn down that cabin to get Mr. Dorner out, the tear gas canisters that we used, first off, we used a presence when we showed up, secondly we used a cold tear gas, then we used the next tear gas was that that was pyrotechnic, does generate a lot of heat, we introduced those canisters into the residence, and a fire erupted." Dorner is accused of killing four people - including Sheriff Deputy Jeremiah MacKay, who was shot dead during the cabin standoff.