"See all those people out there?! Huh?! They're all gonna know me!"
Michael was born in Joliet, Illinois, to Vincent and Lorraine Peterson and was raised in a poor household. Vincent was later sent to prison for two counts of armed robbery and served most of his sentence at Stateville Correctional Center, where mass murderer Richard Speck and serial killer John Wayne Gacy were also imprisoned. Michael and Lorraine visited Vincent every weekend, and during those visits, he observed the inmate hierarchy, in which serial killers would be at the top in terms of respect while snitches and pedophiles were at the bottom. It was also presumed that he may have seen Speck during some of the visits, and possibly even interacted with him, judging by Michael's conversation with the boy. This exposure triggered in Michael a deep fascination of serial killing, as well as a passion for extreme thrill-seeking and a desire to gain the respect his father never got. In March 2005, Vincent had to be transferred out of Stateville Correctional and into Regan Penitentiary for his own safety, after he was stabbed repeatedly and nearly killed when he was about to testify against his partner-in-crime. Michael later started picking fights at school, resulting in him being expelled from four different schools. On November 7, 2006, Lorraine, who raised Michael alone for most of his life, died of a stroke.
In 2010, Michael got a job as a deckhand for a crab-fishing vessel, allowing him to easily seek out thrills due to the dangers of the job. When his father died in 2014, he took advantage of his job to begin serial killing in different countries. For his crimes, he chose to emulate the M.O.s of the most infamous serial killers of the past, as a way to seek out more thrills through the pressure of being actively sought by the public. His first murder occurred on September 12, 2014, at Rostov, Russia, where he raped, mutilated, and killed a girl named Natasha Dudechenko in an emulation of the M.O. of Andrei Chikatilo, "The Rostov Ripper". Michael was spotted at the crime scene by Russian police, but he managed to escape before they could apprehend him. In March 2015, Michael arrived at London, England, and began killing prostitutes in the Whitechapel area, as an emulation of Jack the Ripper. Interpol became aware of the murders and assisted investigators in tracking Michael down, with Emily Prentiss taking supervision of the joint investigation. Prentiss eventually got the idea of luring Michael out with an undercover officer and selected Detective Inspector Louise Hulland for the job, despite the higher-ups' disapproval of the idea. However, the operation failed, resulting in Louise's murder and Michael's escape. The botched operation has since traumatized Prentiss.
"Who's next? You? You. Decisions, decisions! ...You win, rich girl!"
Michael is first seen in Prentiss' flashback about the undercover operation. In the middle of the operation, Prentiss came into the warehouse to rescue Louise. Once she found her, badly wounded from multiple stab wounds, Michael appeared and incapacitated Prentiss. Prentiss grabbed her handgun and shot at Michael, but he was protected by a bulletproof vest. He started to laugh at Prentiss' attempts to kill him before escaping. Louise died from her injuries afterward. In the present day, Michael returned to the U.S. and continued to commit more murders in 2016. First, he emulated the Boston Strangler's M.O. in Boston in August. A month later, he proceeded to the Bronx, New York City, to emulate David Berkowitz. His emulation of Berkowitz's first shooting alerts Prentiss, who calls in the rest of the BAU to help her in the investigation. Michael is then seen in his hotel room cleaning up his bloodied clothes in the sink. Afterwards, he goes to the main room, where he listens in on a Discovery Channel episode about the life cycle of salmon. He sits on the bed, grabs his revolver, and opens it. Then, he grabs a bullet, puts it in his mouth, and plays around with it. Afterwards, he takes it out, puts it in the gun, closes the chamber, and lies down on the bed. Meanwhile, Monica DeJesus, who was shot in the leg by Michael but left alive by him as part of the emulation, is interrogated by Prentiss and JJ, and provides a composite sketch of Michael.
The following night, Michael spots a wealthy couple, Trent and Rhonda Klein, in Queens. Whipped into a frenzy by their affluence, he kills them in an emulation of elements of Berkowitz's second and sixth shootings. When he is spotted by police entering the warehouse a block away, the BAU is informed, but they miss him and instead arrive at the scene of the Kleins' deaths, which frustrates Prentiss. Later, Michael returns to his hotel room, where he is seen packing up his gear and then leaving. Then, he travels to Chicago by taking a bus. During the bus ride, Michael reads a book about America's most infamous killers. Just then, he notices a boy sitting across from him staring at him and trying to read the book, and he tells him that it is not polite to stare. Michael then starts talking to the boy and gives him a bullet, which he claims is lucky because it doesn't have the boy's name on it. The next morning, the bus arrives in Chicago in a bus depot. The passengers start to get off the bus and the boy tries to give Michael back the bullet, but he tells him to be quiet, keep the bullet, and not to tell his mother about their conversation. The boy hides the bullet from her and they both leave the bus. Before the boy gets off, Michael says goodbye to him by imitating a gun being fired and the boy does the same thing.
After Michael leaves the bus, he goes to Northeast State University in nearby Evanston with the intention of emulating Richard Speck's attack on a townhouse. He wanders around and eventually approaches a student named Megan Ross, striking up a friendly conversation with her. He pretends to be a new professor and asks where Mason Hall, a sorority dormitory, is, claiming to be meeting an assistant there. All the while, he eyes Megan's jewelry, and when she leaves, he frowns bitterly at her. The following night, at Mason Hall, Megan's roommate Charlotte comes into her room and tells her about a serial killer that the FBI is looking for. When shown a wanted poster with Michael's photo, Megan is shocked and tells Charlotte about her earlier encounter with him. They both call the FBI hotline but are interrupted by Michael, who steps inside the room and orders Megan to put the phone down, which she does. He then takes both girls hostage and forces them to another room. When a student named Kasey answers Megan's knocks and opens the door, Michael takes her hostage as well. Once everyone is inside the room, Michael kills Kasey. Afterwards, he drags Kasey's body to another location. Megan takes advantage of Michael's distraction to grab a nearby pair of scissors. Michael then reappears and holds both girls at gunpoint, taunting them and asking out loud who he should kill next.
Eventually, Michael chooses Charlotte, but when he is about to kill her, Megan stands up, yells at Michael to let her go, and tries to stab him with the scissors. However, he grabs her arm and stops her, but both girls manage to hold onto Michael's arms, which causes his revolver to go off. The BAU, having just arrived at Mason Hall, are alerted to Michael's location by the gunshots. Charlotte bites Michael's arm, which causes him to drop his revolver. Then, in a fit of rage, he throws Charlotte onto the bed and subdues Megan by throwing her against a picture frame, causing her to drop the scissors. Charlotte manages to escape, finds the BAU, and tells them that Michael is going to kill Megan. Prentiss, JJ, and Rossi step inside the room, as Michael holds Megan at gunpoint. Though he threatens them that he will kill her if they come close, Prentiss steps forward and reminds Michael about their encounter in London. This surprises Michael, who comments that she followed him all the way to the U.S. She then adds that police agencies all over the world are looking for him. The agents then try to talk him down by telling him that he will be all over the news if he surrenders. Embellished by this, Michael starts ranting about how they are going to write books about him and how everyone in the world will know about him. When he turns his head towards the window to observe responding police officers, still ranting, Prentiss shoots Michael through the side of the forehead in mid-sentence, killing him instantly.
As Michael copied the M.O.s of infamous serial killers, he killed his victims through a variety of means, such as strangulation, throat slashing, and shooting. In the case of Natasha Dudechenko, he raped her to emulate the sexual assault Andrei Chikatilo performed on his victims, most notably his first victim, nine-year-old Lena Zakotnova. He originally went out of his way to emulate every detail of the original murders, by operating in the same areas and even shooting a victim but allowing her to live in order to emulate David Berkowitz's first shooting.
However, in his later killings, he became increasingly less focused as he channeled his rage towards people of affluence. By the time he attempted to emulate Richard Speck during the attack on Mason Hall, he ignored the more important aspects of Speck's M.O.: he targeted college students at a sorority dormitory instead of nurses at a townhouse, staged his attack in the northern and more affluent side of Chicago instead of the southern side, shot his victims instead of stabbing or strangling them, apparently had no intention of raping or torturing his victims, and attacked three victims instead of eight (likely because it was the most reasonable number of potential victims he could achieve)
His signature was loitering at the scenes of the killings so he could be spotted by responding police officers and get a rush out of narrowly escaping them. He would always kill his victims between the months of March and September since he would be busy working as a deckhand between October and February.
"They're gonna write books about me! I'm even gonna make you famous..."
The unsub is a narcissistic copycat killer. While most copycats emulate other murderers due to either low self-esteem, identity issues, or low confidence, this unsub is different as he has high confidence in himself. He is brazenly copying high-profile murders and he is currently doing so locally. The fact that he is only active between the months of March and September means he has a way to make money between the months of October and February in order to finance his crimes; it is probably a cash business occupation so he does not leave a paper trail. Given his particular skill set, he is likely a thief, drug dealer, or a member of an organized criminal organization. He is extremely mobile, so he may be going to an airport, train station, or bus station that could take him to the location where he will kill next. His fascination with serial killers is deeply embedded in his psyche and is part of what drives him, meaning he was exposed to the subject at a young age. He may be a victim who survived, related to a victim who survived or was killed, or even connected to a perpetrator.
Outside of his copycat murders, Michael seems to have been based on Ted Bundy. Both were psychopathic serial killers who devolved, had a habit of charming their female victims, operated in multiple states, had varying M.O.s (which included strangulation), and attacked on a sorority house. Both also killed a young girl as their first victims, though it wasn't actually confirmed in Bundy's case.
Michael's obsession with serial killers seems to be based on Stephen Griffiths, a narcissistic serial killer who, like Michael, owned books about infamous killers and had deep fascination with serial killing from an early age, going as far as to tell probation officers and psychiatrists that he fantasized about being a serial killer. Also, both were regarded as violent juvenile delinquents, classified as psychopaths, lived most of their childhood and adolescence with their mothers, and had parents who were criminals; Stephen's mother, Moira, was a con artist convicted of fraud. Though not exactly a copycat killing, the way Griffiths chose Bradford to commit his prostitute murders in order to "honor" another serial killer, Peter Sutcliffe, is similar to how Peterson copied the M.O. and exact areas of operation of serial killers from the past as a tribute to them.
Michael is also partially similar to South Korean criminal Yoo Young-chul. Both were serial killers who lived in poor households as children, which led to them resenting the wealthy, and had varying M.O.s. In both cases, they also left one of their female victims for dead, who would later be found by people connected to them, only for them to die from their wounds.
- September 12, 2014, Rostov, Russia: Natasha Dudechenko (raped, mutilated, and fatally strangled; mutilated again and removed her eyes and tongue post-mortem; based on Andrei Chikatilo)
- March-April 2015, London, England, U.K.: The Jack the Ripper-based killings:
- Allison Cobb (eviscerated and her throat slashed)
- Carol Archer (eviscerated and her throat slashed like the previous victim)
- Detective Inspector Louise Hulland (stabbed in the stomach, slashed her throat, and left for dead)
- Emily Prentiss (incidental; assaulted after she found Louise)
- 2016, U.S.:
- August, Boston, Massachusetts: Unnamed woman (sexually assaulted, then strangled with nylon stockings; based on the Boston Strangler)
- New York City, New York: The David Berkowitz-based shootings:
- September 11: Camille Harrison and Monica DeJesus (both shot with a .44 Charter Arms Bulldog revolver; based on Berkowitz's shootings of Donna Lauria and Jody Valenti):
- Camille Harrison (shot once in the head)
- Monica DeJesus (assaulted; shot once in the leg and left alive)
- September 12: Trent and Rhonda Klein (both shot repeatedly with the same revolver; partially based on Berkowitz's shootings of Carl Denaro and Rosemary Keenan, and Alexander Esau and Valentina Suriani):
- Trent Klein (shot seven times and stuffed his own watch down his mouth post-mortem)
- Rhonda Klein (shot at least six times)
- September 11: Camille Harrison and Monica DeJesus (both shot with a .44 Charter Arms Bulldog revolver; based on Berkowitz's shootings of Donna Lauria and Jody Valenti):
- September 13, Evanston, Illinois: The Mason Hall shooting and standoff (based on Richard Speck's townhouse attack):
- Megan Ross (assaulted and intended to kill; later held at gunpoint)
- Charlotte (assaulted and attempted to kill)
- Kasey (shot once in the head with a revolver)
- Michael is based on a number of unsubs in the show's history and has the most inspirations out of any other unsub (with a total of eighteen). They are:
- Jerry Tidwell, who appeared in Season Ten. Both were serial killers who were active in the U.S. and foreign countries; were triggered to commit their murders after one of their male relatives died; worked in the fishing industry, occupations that they took advantage of to travel around to commit their international killings; and were shot and killed while holding a female victim at gunpoint.
- Eric Olson, who appeared in Season Four. Both were psychopathic serial killers who devolved, copied the M.O.s of famous serial killers from the past, including Jack the Ripper and David Berkowitz, Son of Sam, and who killed someone close to the investigation (Michael killed an undercover police officer, while Eric killed a college student independently investigating his murders), which subsequently caused a BAU member connected to these victims to feel responsible and take said investigation on a personal level. Also, at one point, Lewis assumed that Michael might be trying to search for an M.O. he could personally get off on, much like what Eric was doing.
- Caleb Rossmore, who appeared in Season Seven. Both were organized serial killers who copied the M.O.'s of real-life serial killers, are based on real-life serial killers (Micheal is based on Ted Bundy; Caleb is based on Heriberto Seda), killed their first victims (who were also children) by strangling them, and committed a double homicide in which they killed a couple in their car by shooting them with a revolver.
- Daniel Dryden, who appeared in the novel Killer Profile. Both were serial killers who devolved, copied the M.O.s of famous serial killers from the past, including Berkowitz, and killed a member of law enforcement. Both also went out of their way to emulate the M.O.s almost exactly, all the way down to the approximate location of where the original murders occurred. In addition, their last attacks involved unsuccessful attempts to copy the M.O. of Richard Speck.
- Aspects of Michael's M.O. are similar to many previous criminals who have appeared on the show:
- Carl Buford and Hugh Rollins sexually assaulted their underage victims before strangling them.
- Ryan Phillips raped and strangled his first victim, then mutilated her post-mortem.
- Earl Bulford killed his last five victims by slashing their throats and removed his victims' eyes out post-mortem.
- Mark Jackson cut out his last victim's tongue post-mortem.
- Ronald Boyd removed the eyes and cut out the tongue of one of his victims post-mortem.
- Sarah Danlin killed and eviscerated her victims in the same way as Jack the Ripper.
- Eddie Mays slashed his third victim's throat and eviscerated her.
- Franklin Graney and Patrick Murphy both killed their victims in their homes by strangling them with a ligature.
- George Foyet killed his victims by either shooting them with a revolver or stabbing them with a knife.
- Danny Lee Stokes repeatedly shot two of his victims at night while they were in a vehicle, having to reload at least once.
- Claire Dunbar stuffed her third victim's watch down his mouth post-mortem.
- In addition to the above similarities, one scene, in which Michael puts a .44 bullet in his mouth and plays around with it before taking it out and loading it into a revolver, seems to be a callback to Billy Flynn, who had a habit of licking his own .44 bullets before loading them into his revolver.
- ↑ While Speck was indeed imprisoned at Stateville Correctional, Gacy was not in real life; he was actually executed at that prison, while he was incarcerated on death row at Menard Correctional Center
- ↑ The fictional Northeast State University, while stated to be in Chicago, was clarified to be in Evanston in this CBS article, as a reference to its real-life counterpart Northwestern University