Professor William Hill is a professor and a victim of a leshi.
William is working late in the evening when his maid, Consuela Alvarez, stops by his office and tells him good night before she leaves. As he is working, the temperature suddenly drops in his office. William slowly looks around to find he's face to face with an angry Abraham Lincoln. Lincoln grabs William by the throat and pushes him up against a wall, which is soon splattered by an explosion of blood that also lands on a framed copy of the Emancipation Proclamation.
The next morning, Sam and Dean Winchester visit the scene, and find Sheriff Carnegie. The professor was killed by a gunshot to the head but Sam points out that there is no bullet or powder residue on William's body. The sheriff suggests it could be professional killers like in Michael Clayton. Sam and Dean find out there was a witness, but the sheriff says she is making no sense at all. Sam asks her for a description of William's killer, and she tells him it was a tall man with a beard, wearing an old style tall hat. Dean mentions Abraham Lincoln, and Consuela confirms that yes, President Lincoln killed Mr. Hill. Sam and Dean are reasonably confused.