George Foyet, "The Reaper"
Played by C. Thomas Howell, he is first seen in the Season 4 Episode "Omnivore." Ten years earlier, Hotch and a local detective named Tom Shaunessy had been hunting a serial killer known as The Boston Reaper, who always wore a mask and black clothing and would kill couples along highways in Boston at night. Between 1995 and 1998, he had attacked 21 people, only one of which survived, until Shaunessy made a deal to stop hunting him, which was successful. As a result, the FBI, having never developed a working profile, was unable to catch him. Hotch and his team are called up to Boston because Shaunessy is dying and knows that his demise will cause the Reaper to start killing again, which is proven true that night.
George Foyet is supposedly the only surviving victim of The Reaper. Hotch and Rossi pay him a visit to get information. Hotch and Rossi offer him protection, but he refuses to let The Reaper's attack drive him out of Boston. Hotch gets a call at his hotel from The Reaper, who offers him the same deal that was offered to Shaunessy. Hotchner blows him off, and in anger, The Reaper steps onto a nearby coach bus and shoots everyone on board. When the team arrives at the crime scene, they find each of Foyet's three addresses written in blood on the windows. The team then rushes to Foyet's latest address, where Morgan is knocked out by The Reaper. The Reaper vanishes, but not before stealing Morgan's badge and leaving a bullet behind to taunt him. After Morgan regains consciousness, the BAU finds a large amount of Foyet's blood. It appears that Foyet had been murdered by The Reaper, but his body is not found.
Garcia digs through Foyet's records, and finds out that he had been a substitute high school teacher, but was fired for sexual assault on a girl. Hotchner then recalls Foyet's earlier statement about his fiance's murder: "Do you know long it takes to stab someone 67 times?" Based on the sexual assault charge, and knowing too many details about the murder, Hotch concludes that George Foyet is The Reaper, and that he had stabbed himself to inject himself in the investigation. A reporter named Roy Colson who is writing a True Crime novel about The Reaper is meeting with Foyet at a previously unknown fourth address, and Garcia tracks it from the reporter's cell phone. George Foyet then reveals his true identity to Colson, angry because he had written that The Reaper was either dead or in jail. While holding Colson at gunpoint, the BAU storms the house and arrests Foyet without incident. However, while in jail, he inflicts an open cut on his hand and makes himself appear to be vomiting blood. When he is rushed to the infirmary, he escapes the prison.
Foyet later reappears at the end of the Season 4 episode ("...And Back"), when he surprises Hotchner at gunpoint in his own apartment, saying "You should've made a deal." A shot is heard as the episode cuts to black. In the Season 5 premiere episode ("Nameless, Faceless"), when Hotch does not show up to work, Prentiss goes to his apartment to check on him. She finds a pool of blood and a bullet in the wall. Prentiss coordinates with Garcia, who has been calling ERs with Hotch's description, and Garcia finds out that someone dropped off an "FBI Agent Derek Morgan." However, Morgan is accounted for, meaning that The Reaper dropped off Hotchner at the ER with the credentials previously stolen from Morgan, and let Hotchner live. Through flashbacks, it is revealed that Foyet had shot the wall next to Hotchner. Hotch tried to take him down, but Foyet prevailed in the struggle. He then stabbed Hotch 9 times, but did so only to wound him. When Hotch wakes up, he figures out that Foyet let him live because he intends to go after Haley and Jack. The BAU then raid Haley's apartment, where they find her and Jack unharmed. At the end of the episode, Hotchner places his family under the protective custody of the US Marshal Service.
At the end of the Season 5 episode "Outfoxed", it is revealed that Foyet had been sending letters to Karl Arnold aka The Fox, a serial killer Hotch and the team put away in Season 1. In the following episode, "100", the team becomes hot on Foyet's trail again after finding an alias, Peter Rhea, that Foyet had been using to buy painkillers with at area pharmacies. They find his apartment and storm it, but find that he has already left, and is carrying several guns. They go to the home of US Marshall Sam Kassmeyer, the Marshal assigned to protect Haley and Jack, where he has been shot 3 times, missing 2 fingers, and has been left for dead by Foyet. Right before he dies, he reveals that Foyet took his phone and had gotten a hold of Haley. Foyet called Haley, posing as a US Marshal, and stated that Hotch was dead and that she needed to relocate. He manages to lure her to her own house.
Hotch figures this out, and rushes there to save them. Foyet has Haley call Hotch, and she then determines that she is in danger. Hotch manages to tell Jack in code to hide in a hope chest until he gets there. Hotch arrives at home too late to save his ex-wife, and finds Foyet hiding behind a curtain. He shoots Foyet in the chest several times, but he lives due to the bulletproof vest he is wearing. A struggle ensues between Hotchner and Foyet. Hotch gets the upper hand and forces Foyet to the floor and beats him until he surrenders. However Hotchner, overcome with grief and rage, beats Foyet to death, where his team finds him, stricken with grief and still thrashing the corpse of Foyet. Morgan pulls Hotch off of Foyet and briefly comforts him, telling him "it's over, man." Section Chief Erin Strauss refers to the crime scene as a "bloodbath".
Read more about this topic: List Of Criminal Minds Characters, Memorable Unsubs