Investigators have zeroed in on the spot where the deadly Waldo Canyon fire first sent smoke and embers soaring into the air. That critical step came as homeowners continued to sift through the ashes of the 346 homes destroyed in the deadly fire. The eight-agency team investigating the 18,247-acre blaze reached the fire’s point of origin, leaving it with the painstaking task of mapping the area and searching for clues on the fire’s cause, said El Paso County sheriff’s Lt. Jeff Kramer.