On May 31, 2014, in the Milwaukee suburb of Waukesha, Wisconsin, two twelve-year-old girls attempted to stab their classmate to death. Morgan Geyser and Anissa Weier’s violence was extreme, but what seemed even more frightening was that they committed their crime under the influence of a figure born by the internet: the so-called “Slenderman.” Yet the even more urgent aspect of the story, that the children involved suffered from undiagnosed mental illnesses, often went overlooked in coverage of the case.

Slenderman: Online Obsession, Mental Illness, and the Violent Crime of Two Midwestern Girls tells that full story for the first time in deeply researched detail, using court transcripts, police reports, individual reporting, and exclusive interviews. Morgan and Anissa were bound together by their shared love of geeky television shows and animals, and their discovery of the user-uploaded scary stories on the Creepypasta website could have been nothing more than a brief phase. But Morgan was suffering from early-onset childhood schizophrenia. She believed that she had been seeing Slenderman for many years, and the only way to stop him from killing her family was to bring him a sacrifice: Morgan’s best friend Payton “Bella” Leutner, whom Morgan and Anissa planned to stab to death on the night of Morgan’s twelfth birthday. Bella survived the attack, but was deeply traumatized, while Morgan and Anissa were immediately remanded into jail, and the severity of their crime meant that they would be prosecuted as adults. There, as Morgan continued to suffer from worsening mental illness after being denied antipsychotics, her life became more and more surreal.

Slenderman is both a page-turning true crime story and a search for justice.

Praise for Slenderman:

Named a Best Book of the Year by Audible and CrimeReads
Named a Most Anticipated Book by The Rumpus

“Hale spent seven years poring over thousands of pages of court documents, police reports and other public records . . . The lesson of Slenderman is not about tracking your kids’ internet usage, evolving friendships, or enthusiasms and aversions. It’s that serious mental illness can manifest in people who seem far too young to have such adult problems.”—Lisa Levy, New York Times Book Review

“Hale’s compassionate look at the case is a compelling yet harrowing read that reveals how a seemingly innocent childhood friendship could lead to such a devastating outcome.”—Mae Anderson, AP News

“With clear-eyed prose and deep legal research . . . Slenderman is a skilled and detailed retelling of a story that still mystifies many years later . . . Hale’s intervention into this recent saga of American moral panic is a fulsome, if sobering, story of misdirected pre-teen social angst and cyberspace obsession. Slenderman may have been debunked in the popular imagination but he lives on as an enduring metaphor for the shadowy corners of the internet and the corrupting danger that our online existences can have to our offline realities.”—Nathan Smith, New York Observer

“A gripping read about a true crime that could have been averted.”—People, “Best New Books”

“Slenderman is a book that asks its readers to approach difficult, stigmatizing subjects—mental illness and criminal justice—with an open mind. Watching the story unfold and knowing the fate that everyone involved is heading towards often had my pulse racing . . . A cautionary tale for all of us.”—Jasmine Gonzalez, Porchlight Books “Staff Pick”

“A balanced, well-researched, and thoughtful account of an extremely sensational case and its even more sensational aftermath . . . A must-read for anyone interested in this case.”—Jesyka Traynor, True Crime Index

“Searing . . . As the first researcher into the case to draw extensively from transcripts of vital records, Hale has produced what stands as the most accurate account to date of this horrifying episode. This is a must for true crime fans.”—Publishers Weekly (starred review)

“The Slenderman case can seem impenetrably bizarre, but Hale nimbly documents the numerous contributing factors to the online legends, the crime and its judicial outcome . . . Moreover, Hale is originally from Wisconsin, providing her well-developed true-crime narrative with an insider’s take on social and cultural norms that fostered the communication breakdown among authority figures who might have tuned into the suspicious circumstances before a crime could be committed . . . [Hale’s] steady narrative vision brings clarity to a thoroughly upsetting situation.”—Shelf Awareness

“A page-turning true-crime story as well as an eye-opening look at the treatment of convicts experiencing mental illness . . . An engrossing account that is sure to include new information even to those familiar with the shocking story.”—Booklist

“Kathleen Hale’s Hazlitt piece on the Slenderman story still stands out from the general sensationalist coverage of the case for its level of empathy for all involved. When two middle schoolers stabbed another middle schooler in the woods in 2012, they claimed to do it on behalf of a mysterious figure known as Slenderman. Hysterical parenting sites spread a moral panic about CreepyPasta, the website where stories of Slenderman originated and then became memes. However, undiagnosed schizophrenia, midwestern stoicism, and intense friendship dynamics are much more to blame for the attack, as Kathleen Hale illustrates here.”—CrimeReads

“Hale breathlessly recounts this unspeakable tragedy but holds her focus on the courtroom and society’s failures in treating the mentally ill. Her message is resonant: We must do better for those in need . . . Beyond the horrific incident at its center, the book expands into a searing criticism of how society treats (and mistreats) the mentally ill. A relevant true-crime cautionary tale as well as an urgent plea for mental health awareness.”—Kirkus Reviews

“Inside this intimate, plain-spoken masterpiece lies a haunted secret garden of feverish childhood fears and fantasies. It’s a shadow world for which nothing can prepare you, and one which I doubt you’ll ever be able to shake.”—Walter Kirn, author of Blood Will Out: The True Story of a Murder, a Mystery, and a Masquerade