Investigators have started interviewing witnesses to a massive fire that destroyed a beef cattle auction business in Lexington. Lexington Fire Department spokesman Joe Best said Sunday that it's too early to determine the cause of the fire and exactly where it started. Saturday's fire destroyed seven acres of the stockyards operated by the Blue Grass Livestock Marketing Group. No one was injured. The flames also consumed several nearby businesses. Best says officials are interviewing a large number of potential witnesses, including business owners. The fire churned up a plume of thick, black smoke that darkened the skies for miles. Best says firefighters continued putting out smoky hot spots on Sunday as gusty winds picked up.