Hall County Fire Services investigators spent Tuesday night and Wednesday trying to discover the cause of a fire destroying a 5,000-square-foot home on Lake Lanier. “We do know we had a natural gas line somewhere whether it was to the grill or the natural gas line furnishing the house,” Hall County Deputy Fire Chief Chad Black said. Two people in the house, who declined to comment, escaped with their dog after noticing flames in the back left corner of the home in the 5700 block of Harbor North in the Hidden Harbor subdivision.