"Do you ever wonder what's under your skin?"
Born on February 6, 1997, in Newton, Iowa, Jeremy was despised by his religious mother Kendra from the day he was born. Her hatred of him stemmed from her initial pregnancy with twins, with the other child later being consumed by Jeremy while they were still in the fetal stage. When Jeremy was ten years old, his father left the family and moved to Wisconsin. By the age of thirteen, Jeremy had already established a juvenile record including several crimes, such as four counts of petty theft, three counts of assault, four counts of battery, one charge of sexual assault, and one count of animal cruelty. Also, according to Kendra, he had tried to kill his entire family by placing rat poison in their Thanksgiving turkey and killed their neighbor's dog. On October 10, 2010, he twisted the arm of his sister, Carrie, so far that it broke and she had to be taken to the ER. A doctor became suspicious and contacted Social Services, who filed a report on the incident. At this point, his mother could no longer put up with him and left him at a hospital in Nebraska, intending for him to be applied for the state's Safe Haven child protection law. For the paperwork, he claimed his name was Niko Bellic. Nine days later, while he was there, he was picked up by Monica Archer, who did volunteer work there, and was allowed to spend the night with her family. That same night, he killed the entire family and began his spree of familicides as he fled back to his home at Newton, intending to seek revenge on Kendra and Carrie.
"I'm thirteen. I'll see her in five years anyway."
After killing the Bennett family, Jeremy hitches a ride with Reverend Louis Hannum. While on the road, Jeremy, most likely acting out on his psychopathic tendencies, murders Hannum, causing his car to crash into a ditch, then dissects Hannum's arms. He then walks to a park and spots the Riverton family, who has stopped by as the daughter Amber wants to go to the bathroom. Jeremy gains the trust of the mother Nancy by saying that he got off a bus heading for Chicago to go to the bathroom, but the bus left before he can get back and his cell phone is still onboard. Nancy decides to drive him to the local police station, but after they witness officers struggling with a gangster, she changes her mind and brings Jeremy home instead, much to the enjoyment of Amber and the son Zack. There, Jeremy gives Nancy the Archer family's home number before being distracted by Nancy cutting up chicken with a kitchen knife. Meanwhile, Rossi and Reid go to the Archer home, having realized that the unsub is a teenager and that Monica Archer willingly took him home because she trusted him. There, they find a message sent by Nancy about Jeremy being at her house; since neither Monica's sons were named Jeremy, they realize that Jeremy had already attacked another family.
Morgan and Prentiss rush to the house and find the children tied up and Jeremy and Nancy missing. In Nancy's van, Jeremy talks with her and criticizes Zack before eerily stating that Amber will become "hot" when she grows up. Nancy then pulls over at Jeremy's request, and Jeremy asks if she is relieved that he will be out of her hair. When Nancy denies it, Jeremy angrily stabs her in the stomach before stealing a skateboard and riding off. By the time the BAU identify him, Jeremy has made his way back to his home in Iowa and taken his sister hostage. When Kendra confronts him, he forces her to admit what happened to his unborn twin. Morgan and Prentiss then burst into the house and hold him at gunpoint. When Jeremy claims that they can't shoot a kid, Morgan promises to kill Jeremy if he even considers harming his sister, causing Jeremy to tearfully surrender. While being escorted from the house by Morgan, he smugly proclaims that "he would see [his mother] in five years", believing that he will be released at eighteen. Morgan tells him to not count on it and vows to attend every one of his parole hearings to prevent that from happening before shoving him in the police car and slamming the door on him. The BAU later mention that Nancy survived her stab wound and that they plan on keeping Jeremy's case-file on hand in case he is eligible for parole.
Jeremy usually targeted Caucasian middle-class families, but as exemplified by his out-of-character murder of Reverend Hannum, he also wasn't hesitant in attacking other victims. He would gain their trust using some kind of ruse, such as saying that he missed his bus, in order to gain access to their homes. Since he was only 13, they felt comfortable enough to let him stay in with them. After tying the children's arms behind their backs, all the while telling them it was a game, Jeremy then lured the parents to them somehow and tied the father's arms behind his back and tied the mother's arms to a chair. Then, he would strangle the children with a ligature and stab the fathers to death with a kitchen knife in order to torture the mothers (who were surrogates for his mother) psychologically, after which they would be brutally bludgeoned to death with some incidental object. During his second family massacre, Jeremy dissected the father's torso out of curiosity and did the same to Reverend Hannum's arms.
"You think I'm a bad kid."
"I never said that."
"You didn't have to."
The unsub is an adolescent white male aged between 13 to 17, who is diagnosed as a "budding psychopath" as he is too young to be classified as antisocial. He is streetwise, but clearly comfortable and easily accepted in a middle-class suburban home. His interpersonal skills are through the roof, and this manipulation is not just a ruse, it is a complex con. Omaha is where his killing spree originated, so it is likely that he is from there; he may have been recently released or escaped from a juvenile detention center or a psychiatric program for boys. He has traveled over forty miles because his victims, not suspecting an average teenager of being dangerous, gave him rides and places to stay. As part of his ruse, he appears as an extremely vulnerable child alone out on the road.
He most likely has a criminal record and grew up in a medium socio-economic status, but his rage against families reveals that he experienced extreme abuse or neglect. At some point, he was removed from his family sometime during the year at a major hospital, most likely the same one where he met Monica Archer, since she worked as a nurse. He has a juvenile record, he is well known to truant officers, and he has probably been kicked out of school, possibly several. He liked tying the Riverton children up with belts and socks and terrorizing them, and he knew what he was doing, which means he has done it before. Budding psychopaths like the unsub do not pick on their siblings, but torture them, so he may have harmed a younger sibling, who was taken to the emergency room as a result in the last six months.
Throughout the attacks, Jeremy had a noticeable habit of trying to invoke a reaction (possibly a violent one) from the mother by stating unsettling facts, such as suggesting he would rape her daughter. During this, he would ask if they hate him, and getting visibly upset if they said no, almost as if he wanted them to hate him, as that would presumably "justify" their suffering and death in his mind.
Jeremy is partially similar to serial killer Craig Price. Both were family annihilators who committed their killings while they were still teenagers, killed their victims in their homes, and used the victims' own knives to stab them. Both were also considered to be released when they reached the age of adulthood despite the brutality of their murders.
Jeremy also bears some similarities to Jesse Pomeroy. Both had one sibling that was considered the "good" one, were abandoned by their fathers, killed pets, gained the trust of their victims (children in Pomeroy's case, families with children in Jeremy's) before tying, beating, and stabbing them; and killed people for the first time in their adolescence. Jeremy also had unspecified antecedents for sexual assault, and there was a sexual motive in Pomeroy's attacks.
- Unspecified date(s): A total of five counts of assault and battery
- Unspecified date: One unspecified sexual assault
- November, pre-2010, Newton, Iowa: Attempted to kill his entire family by poisoning them with rat poison pellets, including:
- Kendra Sayer (mother)
- Carrie Sayer (sister)
- An unnamed maternal grandmother
- October 10, Newton, Iowa: Carrie Sayer (assaulted; twisted her left arm until it broke)
- October 19, Omaha, Nebraska: The Archer family
- Monica Archer (mother)
- Peter Archer (father)
- Eric Archer (eldest son)
- Daniel Archer (youngest son)
- October 20, Council Bluffs, Iowa: The Bennett family
- Sandra Bennett (mother)
- Jake Bennett (father; killed, then dissected his torso and removed his intestines)
- Sammy Bennett (son)
- Kayla Bennett (daughter)
- October 21, Route 6, Iowa: Reverend Louis Hannum (stabbed his throat and then dissected his arms post-mortem)
- October 22, Des Moines, Iowa: The Riverton family (all held hostage)
- Nancy Riverton (mother; abducted, stabbed in the stomach in Newton, Iowa, on the next day, and left to die; was rescued)
- Zack Riverton (son; tied up)
- Amber Riverton (daughter; also tied up)
- October 23, Newton, Iowa: Carrie Sayer (held at knifepoint and intended to kill)
- Sterling Beaumon, the actor who portrays Jeremy, went on to portray a sociopathic killer in Law & Order: Special Victims Unit.
- Being thirteen years old at the time of the episode, Jeremy is the youngest rampage killer on the show to date, and also one of the youngest killers in general.