Plot summary
The death of Leonard "Diddle" Callahan, a computer cryptologist who was the baritone in Gus's old college a cappella group, is suspected of being murdered, by the other two members ( Jaleel White and Kenan Thompson ). Although they both had a falling out with Gus, they ask Shawn to investigate, but he and Gus find themselves stonewalled at every turn by the police, and later, an undercover detective ( Tony Todd ).
Credits
Adapted from Wikipedia contributors, Psych season 4. HTML formatting and reference markers removed.