Troy Riley was a Supporting Protagonist in The Following. He was an agent in the Behavioral Analysts Unit (BAU2) with the Federal Bureau of Investigation, working alongside Agent Jennifer Mason until her transfer and briefly with Debra Parker. He aided former FBI Agent Ryan Hardy during the investigation into Joe Carroll and his followers and cooperated with him at a higher extent than Mason or her successor.
After Joe Carroll makes his escape from the Virginia Central Penitentiary, former FBI Agent Ryan Hardy is flown in to aide in the investigation. Troy and his partner Jennifer Mason meet with Hardy upon his arrival, detailing the the layout of their investigation so far including a mobile command center. He leads Hardy into the security office, where Joe killed five guards prior to his escape and introduces him to Scott Turner (who was already acquainted with Hardy). Turner expresses a smug dislike for Ryan and tells Troy that "he's your problem, Agent".
Riley and Mason bring Ryan to the command center, where various people (referred to as "Carroll's groupies") are waiting to come forward with information. At the helm of a presentation, Mike Weston details info about Carroll and the murders, to which Ryan approaches and offers a more accurate depiction of the man...with Weston's strong admiration showing. After the presentation, a disturbed woman stands up in the middle of the command center and strips down to just her panties...brandishing an ice pick which startles nearby civilians. Troy runs forward, readying the gun in his holster while telling her to drop it and Hardy himself attempts to calm the situation...only for her to drive the pick through her eye and fall to the floor, convulsing before laying dead.
He accompanies Ryan to first Jordan Raines's house and later Sarah Fuller's, finally being among the FBI that tails Ryan to the Lighthouse Breakfast & Grill and is the one to subdue Ryan when he attempts killing Joe. The FBI takes Carroll into custody and transfers him to the Federal Detention Center in Richmond, Virginia. ("Pilot")
While working on the case on Rick Kester, he was taking care of his wife Maggie until he was killed when Maggie Kester ambushed him with a knife after she was revealed to be one of the followers of Joe's cult. ("The Poet's Fire")
- He is the first recurring character to be killed by another recurring character.