The Devil's in the Details ... and in the Upstairs Bedroom

S4 E4: After Agatha (Melanie Bray), a student at a Catholic college, jumps off the roof of a building, Gus drags Shawn to the school to investigate as a favor to an old teacher, Father Westley (Ray Wise). Lassiter and Juliet are already there speaking with Westley and headmaster Father Bard (Tim Conlon), who explain that Agatha was a model student until three weeks ago when she suddenly started acting irrationally. Lassiter thinks it's murder, Shawn is leaning towards suicide, while Father Westley believes she was possessed. Despite being roundly dismissed, even by Father Bard, Westley is insistent and Gus agrees to take the case, over Shawn’s objections.