|“||She was the one. She was special.||”|
— Malone to Walker
Malone suffered from a rare blood disorder, xeroderma pigmentosum, which caused his skin to burn every time he was exposed to light, akin to a vampire. As a result, he was disowned by his parents and sent to live with his uncle, a Vietnam War veteran named Doug Jones who bonded with him. Jones died from a heart attack on February 6, 2007, and left his home and belongings to him, though Malone allowed the home to be demolished and converted into a cash-only parking lot so he could gain his own access to the New York City sewer system. He spent most of his time down in the sewers, listening to all of the sounds from above the ground. At some point, he decided to seek an unconventional treatment for his disorder. As a result, Malone began abducting women and draining them of their blood so he could drink it, believing it to be a remedy of sorts. However, all of these women died after their attempts to escape, having cracked their skulls open when they fell because of disorientation.
On April 1, 2017, Malone abducts another girl, Katie Hammond, and slowly drains her of her blood in the sewers. Days later, he visits her to tell her it is her birthday and asks what she was going to do to celebrate. She replies that she would go out to eat with her family. Malone then has Hammond blow out his candle. The following day, Malone writes about Hammond in his diary while sitting in his van. He then puts his hand into the sunlight and sees that his skin is not burning. Then, he opens a hatch in his van, opens the manhole cover underneath, and climbs down into the sewers to bring Hammond food and Vitamin C. Then, Malone has Hammond ask him a question; she asks if he leaves because he has a job. He confirms it and tells her about a time when he was working, a dead woman had been found nearby, having been there for weeks and no one knew about it. Later, Hammond tries to escape, but she only finds a locked manhole cover. She yells for help, but no one can hear her. The following night, while Malone is working, a female motorist drives up to his post and asks him to tell his boss to get more lights in the parking lot; Malone halfheartedly replies that he will.
The next day, Malone returns to the sewers with food and realizes that Hammond tried to escape when he notices a wound on her foot. He reminds her that it is dangerous, adding that if she falls, she could crack her head. Hammond starts to cry and tells Malone that she needs to see her family. Malone says that he can't release her and that he hates when she cries. Afterwards, while Hammond is eating, Malone informs her that she can hear everyone and everything up in the street level, but no one can hear her from down below. Malone yells out as loudly as he can to make his point, and then tells Hammond about the dark and asks about her parents. He also asks her if she was afraid of the dark when she was young, to which she replies that she was. Then, Malone tells Hammond about how he came to live with his uncle when his parents disowned him. Next, he asks if she believes in fate; she replies that she doesn't believe in it. Then, she asks Malone to let her try to find a way out of the sewers; if she can't, then she will believe in fate again and stay. Convinced, Malone gives Hammond her shoes and tells her to run. While fleeing, she finds a wrench and grabs it for self-defense.
Meanwhile, the BAU locate Malone's van and find his secret passageway into the sewers. They split up; Alvez explores the parking lot with Prentiss, while JJ and Walker go down into the sewers. After entering the sewers, JJ and Walker both split up; JJ finds Hammond, while Walker encounters Malone, who knocks him out. Walker regains consciousness a few minutes later, but is disoriented. Walker picks up his gun and goes looking for Malone. Speaking from the shadows, Malone accuses him of taking Hammond away from him, but Walker retorts that she wasn't his to keep. Then, Walker asks Malone how many other victims he brought to the sewers, and he replies that he lost count. At that moment, Walker pinpoints the direction Malone's voice is coming from, he turns, and shoots him twice. As Malone is lying on the floor bleeding to death, Walker tells him to breathe deeply. However, due to the ringing in his ears from the gunshots, Malone is unable to hear him. Walker recites a meditation from Sri Lanka, which he learned from Garcia earlier. Right before dying, Malone tells Walker that he has never been anywhere, but he won't be 100,000 flies, referencing his earlier story about the dead woman. He then succumbs to his wounds, and his corpse is last seen being taken away on a stretcher.
Malone targeted young brunette women, usually drug addicts, but he started selecting healthier victims as he went along. After somehow abducting them, he would take them to the sewers and hold them captive for a week. All the while, he would use surgical equipment to drain them of their blood, a little amount at a time, and drink the blood. He would also give them food and drinks high in Vitamin C, so they would remain healthy despite the gradual blood loss. The victims' deaths were all unintentional; when they attempted to escape, they would eventually fall over due to disorientation, and crack their skulls open. Afterwards, Malone would clean the bodies with baby wipes and dump them around random areas of New York City at night, posing them in angelic positions beforehand. Because the victims were mostly drug addicts, a connection between the victims was never realized by police because investigators assumed the needle marks on their arms were from heroin needles. When he attacked Stephen Walker, he used a blunt instrument, likely a pipe, to hit him in the head from behind.
No official profile of Malone was made by the BAU.
Malone is partially similar to Richard Chase - Both were psychotic serial killers who had particular conditions which dominated their lives (paranoid schizophrenia and hypochondria in Chase's case, xeroderma pigmentosum in Malone's), were primarily cared for by a single relative (Chase's mother and Malone's uncle, respectively), both had obsessions with curing their afflictions using blood, began killing after their caregivers left them in some way (Chase's mother left him on his own, while Malone's uncle died), and as serial killers they primarily targeted women (though Chase also killed males and Malone tried to kill one), drank their blood under the impression it would help cure their conditions, and had two surviving victims.
- Unspecified dates from 2007 to 2017:
- At least two dozen unnamed victims
- Chloe Pettiman (her body was never found)
- Cynthia Bell (her body was never found)
- Daphne Vicker (her body was never found)
- Nora Farbinger
- Cora Tuchnan
- Grace Lee
- Shelley Gallagher
- Lisa Dewald
- April 1: Katie Hammond (abducted and drained of some of her blood; was released six days later)
- April 7: Stephen Walker (assaulted)
- John Malone is the eighth unsub in the show's history to not have his name revealed by the end of the episode, despite being credited by said name. The previous seven are:
- Season Five
- Season Six
- Season Nine
- Season Ten
- Season Eleven
- Season Thirteen
- Malone has some similarities to Bryan Hughes ("Magnum Opus") - Both were serial killers and abductors who had medical conditions, primarily targeted women (though Hughes killed men and Malone tried to kill one), abducted and bound them so they could drian their blood, dumped their bodies at night (though Hughes later did so during the day), and were shot dead by a BAU member while trying to kill a final victim.