Arthur Swenson was a 20 year veteran of the police force in Ames, Iowa who a year prior was in an accident where much of one his eyes was shattered, and received an eye transplant from Brick Holmes. After killing a pizza delivery man for the annual sacrifice to Cacao, Arthur could not live with himself and allowed himself to be arrested.
While investigation the ritualistic murders happening in Minneapolis, Minnesota; Dean reads about a similar case that involving the arrest of Arthur Swensen in Ames, Iowa. When the Winchesters arrive in Ames to question Arthur, they are met with him repeating the same phrase over and over again, "K'uhul ajaw, Cacao, shi-jiiy. K'uhul ajaw, Cacao, shi-jiiy." As Sam tries to question Arthur, he begins to violently bang his head on the table in the interrogation room, while still repeating the same phrase, Dean pours holy water on his arm, but gets no reaction just Arthur repeating the same phrase over and over again.
Arthur is then taken back to his cell, where he sits on the edge of his bed, rocking back and forth and repeating the same words over and over. He pulls a metal bar from the bed frame and points it at his eye, and proceeds to stab himself in the eyes. He is taken to a hospital where a doctor informs Sam and Dean that he had attempted to remove his eye. It is assumed that he died along with the other recipents of Brick Holmes' organs once Randa Moreno was killed by Dean, although the fact that he had apparently taken the eye out before her death might have saved his life.