i found this bit of information.
And the days keeps on worryin' me,
there's a hellhound (1) on my trail,
hellhound on my trail, hellhound on my trail
-Robert Johnson
(1) Note 1: According to the Webster online dictionary a hellhound is a "dog of hell, named Cerberus in Greek and Roman mythology, the three-headed dog guarding the gate of Hades". It will probably stay a secret for all times what Robert exactly meant by the hellhound, but the image of the hounds of hell, coming to seize sinners, was often used in southern churches.