Atlanta (CNN) -- Authorities in Georgia are investigating the apparent homicide of a Georgia man who produced popular gun-related YouTube videos.
Keith Ratliff was found shot in the head January 3 in his home-office in Carnesville, Georgia, about 80 miles northeast of Atlanta.
Ratliff was co-owner of FPS Industries, whose website says it "is proud to be world leaders in product development and testing for hard use firearms shooters."
Investigators from many agencies -- including the Georgia Bureau of Investigation and the federal Bureau of Alcohol, Tobacco, Firearms and Explosives -- are investigating, and the GBI said Friday that they are making progress in identifying the shooter.
Several guns were found at the scene, but none of them were used to shoot Ratliff, the GBI said in a news release.
Ratliff's YouTube channel had more than 530,000,000 views.
Gun rights group says Georgia home invasion proves their point