Leon Tolliver was a convicted felon from Orlando.
Leon was born as an only child, and he later had a son by the name of Tommy Tolliver. The two either got along or were estranged, however, Tommy eventually became a serial killer like his father.
Leon had a fresh warrant for an assault charge but he suddenly disappeared, approximately one week before his son also disappeared from prison. Police simply assumed Leon fled the warrant.
In truth, Cain had hunted down and killed both Leon and Tommy, due to being his cursed descendants. Cain came close to killing Leon's grandson, Austin Reynolds, but the child was saved by Sam and Dean Winchester.