John Curtis

John Curtis, a.k.a. "The Replicator", was a serial killer and copycat who has been stalking the BAU at least since the start of Season Eight of Criminal Minds.

Background
John Curtis was an FBI Agent who worked on the 2001 anthrax attacks, which Blake also investigated. When the case turned south, both he and Blake were demoted by Strauss. Curtis blamed Blake for his downfall and started stalking her team. The photos seen in his darkroom at the end of "The Silencer" suggest that the stalking began sometime after Prentiss's departure, but before Blake's joining of the team since there are pictures of the latter, but none of the former. This is further supported by his photo of Garcia, in which she is wearing the clothes she wore during the events of the bank robbery in "Hit" and "Run", which may be where Curtis first saw them; in "Carbon Copy", a majority of the photos he keeps seem to have been taken during the bank robbery as well.

The Silencer
Curtis is first seen at the end of the episode, standing in a darkroom and hanging a newly-finished photo of Blake next to photos of the other members of the team.

The Apprenticeship
After the team solves the prominent case, Hotch receives a phone call from Dallas authorities, announcing the appearance of a copycat of John Myers, a.k.a. The Silencer, who has killed a man and sewed his mouth shut post-mortem. He and Rossi discuss about it, believing that it must be a copycat since the Silencer is dead. At the end of the episode, Curtis is seen taking photos of the team during a bureau softball match from his car.

Magnificent Light
Curtis is next seen at a dinner that Morgan and Garcia attend. As Morgan gives a speech, he takes an empty wineglass at Garcia's table that was previously used by Morgan, puts it in a plastic bag, returns to his or her residence, and puts it on a table. From that same table, he retrieves a photo of his third victim, whom he killed by severing his right leg in the style of John Nelson, and hangs it next to a photo of his second victim and under a set of photos of the entire team. Off-screen, he murders his fourth victim, severing his right leg and replacing it with the leg of the second victim.

Perennials
After the BAU conclude the latest case, Hotch and Rossi call the rest of the team into the briefing room. There, they inform them about Curtis's copycat crimes, and Hotch says that the team will be investigating this ongoing case.

Zugzwang
"Zug...zwang."

Curtis made a brief appearance in the episode, calling Reid on a payphone from Maeve Donovan's house. He identified himself as "Adam Worth" and uttered the single word, "Zugzwang". At the time, Reid and the BAU believed that it was Maeve's stalker, Diane Turner, who made that call since Maeve and Reid had used names related to Arthur Conan Doyle in their correspondence.

Broken (Part 1)
Curtis was seen at the end of the episode, watching live news coverage of the BAU raiding a conversion camp that was using illegal methods. He then views photos of his victims, where it is revealed he has already killed a woman in the style of Adam Rain. Finally, he views a video of Blake's lecture on linguistics and then looks at the cover of a book written by her.

Carbon Copy (Part 2)
In the beginning of the episode, Curtis sends JJ a bouquet of flowers with a card reading "Zugzwang". Reid then realizes that it was Curtis who called him on the payphone, not Diane. Throughout the episode, the BAU assumed that Donnie Bidwell was the Replicator, as he was killing women based on the M.O. of killer artist Bryan Hughes. Towards the end of the episode, however, the team realized that Curtis convinced Donnie to commit the Bryan Hughes-based murders while he killed a woman in Pittsburgh, Pennsylvania, in the style of killing team David Turner and Toby Whitewood. At the end of the episode, the BAU arrive at a location in Pittsburgh, where they find the woman's body, the hammer used to kill her, and dozens of photos of the team, all surrounded by "Zugzwang" words written in red.

Brothers Hotchner (Part 1)
He was taking pictures of the Hotchner brothers. His face was finally revealed at the very end of the episode as he stood over Strauss in her hotel room.

The Replicator (Part 2)
He was taking over & controlling the team. After killing Strauss, he disabled the helicopter that Hotch, Reid, Blake and a pilot were flying in. Using a smoke bomb that knocked them all out, he captured Blake, chaining her to a chair that had pressure sensor. When she came to, Curtis explained his rage and motives to her. He left her to die, along with the team who came to rescue her. When Blake was freed, she got out of the chair, which started a timer linked to explosives. Garcia managed to delay the timer, but only for a short time. Curtis later came back to learn that they had escaped. He was then confronted by Rossi, who had freed his teammates. Curtis attempted to trap himself and Rossi the same way that had the team, by sitting on the pressure-sensor chair then getting back up. However, Rossi revealed how he opened the door, using Strauss' AA coin. Rossi left Curtis trapped in the room, who died in the explosion.

Profile
The unsub is a white male in his mid 40s, possibly in his late 50s. He is criminally and forensically sophisticated, so he may be an ex-convict or have law enforcement training. He is using his victims as a device with which to antagonize the FBI, particularly the BAU team by copycatting murder cases that the team had closed all over the country. He stalked each member of the team, which means that he is mobile and has the time and means with which to get around and the intelligence to cover his tracks and remain evasive.

Modus Operandi
During Curtis's known killings so far, he or she copied the M.O. of unsubs the BAU team have captured during the course of Season Eight:


 * The second victim was killed the same way John Myers, a.k.a. The Silencer, killed his victims, by fatal asphyxiation and then sewing his mouth shut post-mortem. A major difference to this particular murder was that the victim, a man, was specifically targeted.
 * The third victim lost his right leg and died of blood loss, with the fourth victim losing his right leg as well and having it replaced with the leg of the third victim; this was the same way killer surgeon John Nelson killed his victims. A major difference to this particular murder was that the victim whose leg was used as the implant wasn't discovered.
 * The fifth victim was killed by having her limbs dislocated, followed by a fatal hanging from a marionette device and then disposal by stuffing into a box, the same way killer puppeteer Adam Rain killed most of his victims. A major difference to this particular murder was that the victim was a woman.
 * The sixth victim, also a woman, was killed by having her head covered with plastic wrapping and then bludgeoned, the same way killing team David Turner and Toby Whitewood killed most of their victims. A major difference to this particular murder was that the victim was killed in Pittsburgh, Pennsylvania, while the original victims were killed in Miami, Florida.
 * The proxy victims murdered by Donnie Bidwell were all killed by exsanguination and then their eyelids being removed post-mortem, which was the fully-evolved M.O. of killer artist Bryan Hughes, who used said M.O. to kill two of his victims. Major differences to these particular murders were that the victims were all women who were specifically targeted and worked as nurses; they were all murdered within a day's time; and their murders occurred in Philadelphia, Pennsylvania, while the original victims were killed in San Francisco, California.

During at least three of the first four murders, Curtis went to largely-populated cities located near the same cities where the original killers committed their murders. Another difference between Curtis and the serial killers he copied is that the former takes photos of his or her victims after killing them.

Personal Victims

 * 2012:
 * Seattle, Washington: Unnamed woman
 * Dallas, Texas: Maxwell Holmes
 * Unspecified location: Unnamed blond man
 * Las Cruces, New Mexico: An unidentified black man
 * 2013:
 * Phoenix, Arizona: Megan Lowenbach
 * Pittsburgh, Pennsylvania: Unnamed woman
 * Manhattan, New York: Erin Strauss

Victims by Proxy

 * 2013:
 * Philadelphia, Pennsylvania :
 * Molly Patton
 * Sandy Larson
 * Shannon Levin

Appearances

 * Season Eight
 * "The Silencer"
 * "The Apprenticeship"
 * "Magnificent Light"
 * "Perennials"
 * "Zugzwang"
 * "Broken"
 * "Carbon Copy"
 * "The Gathering"
 * "Brothers Hotchner"
 * "The Replicator"