The Billy Milligan Case — Landmark Insanity Defense in Ohio

The Case

The Billy Milligan case is a landmark American criminal case from late-1970s Ohio in which William Stanley Milligan — known publicly as Billy Milligan — was charged with kidnapping, robbing and raping three Ohio State University students and ultimately found not guilty by reason of insanity. The verdict, handed down on December 4, 1978, made Milligan the first defendant in a major U.S. case to be acquitted of violent felonies on the basis of what was then called multiple personality disorder, today known as dissociative identity disorder. The case is considered solved: the offender was identified, arrested, prosecuted and adjudicated within roughly a year of the crimes.

The Crime

In October 1977, three young women associated with the Ohio State University campus in Columbus were abducted in separate incidents, robbed and sexually assaulted. According to court and psychiatric records summarised by later analysts, the attacks shared a similar pattern: the victims were approached in or near campus areas, forced to withdraw money, and then raped before being released. The brutality and seemingly methodical nature of the attacks shocked the OSU community and triggered an intense police response that quickly focused on a single suspect.

Milligan's defense would later argue that the crimes were not committed by a single, coherent personality. According to the psychiatric case material, one alter identity named Ragen — described as a Yugoslav-accented protector figure — was said to have carried out the robberies, while another alter, Adalana, was claimed to be responsible for the kidnappings and sexual assaults. This division of criminal responsibility between alleged alternate personalities would become the central and most controversial element of the trial.

The Victims

The three victims are identified in the available sources only as female students connected to Ohio State University. Their names and ages are not disclosed in the public-facing materials provided, in line with standard practice protecting the identity of sexual-assault survivors. What is known is that all three were young women going about ordinary campus life in October 1977 when they were targeted in the vicinity of the OSU campus.

Investigation

Milligan was arrested in October 1977, only weeks after the attacks began. At 22 years old, he already had a documented criminal history that included armed robbery, which sharpened investigators' attention once his name surfaced. Physical evidence and victim identifications tied him to the attacks, and he was taken into custody by Columbus-area authorities.

The investigation took an unusual turn almost immediately. An OSU police officer who transported Milligan later recalled that it felt as though he was 'talking to different people at different times' during the short ride to headquarters. As detailed in the Wikipedia summary of the case, this behavior prompted defense attorneys to seek extensive psychiatric evaluation. Multiple clinicians independently concluded that Milligan presented with a striking number of distinct personalities — eventually catalogued as 24 — each with its own name, voice, memories and, in some cases, claimed nationality.

Trial and Verdict

The trial, held in Ohio in 1978, hinged almost entirely on psychiatric testimony rather than physical forensic disputes. Defense experts argued that Milligan suffered from a severe dissociative disorder rooted in childhood abuse and that he could not be held criminally responsible because the personalities accused of the acts — Ragen and Adalana — operated without the knowledge or control of the 'core' Billy.

On December 4, 1978, the court accepted that argument and found Milligan not guilty by reason of insanity on all counts of kidnapping, robbery and rape. Rather than receiving a prison sentence, he was committed to the Athens Mental Health Center for psychiatric treatment. The decision was unprecedented in scale: no U.S. defendant had previously been acquitted of multiple violent felonies on a multiple-personality defense, and the ruling sparked sustained legal and clinical debate that continues today.

Today

The Billy Milligan case remains one of the most-cited examples in discussions of the insanity defense, the validity of dissociative identity disorder as a forensic diagnosis, and the limits of criminal responsibility. Milligan was moved between several psychiatric facilities over the following years and was eventually released; he died in 2014. Some later accounts have speculated about possible links to other unsolved crimes, but those claims remain unproven in the sources reviewed for this article.

Public interest surged again with the 2021 Netflix docuseries Monsters Inside: The 24 Faces of Billy Milligan, which revisited the original investigation, the trial and the long aftermath through archival footage and new interviews. The case continues to be taught in psychology and law courses as a defining — and deeply contested — moment in the intersection of mental illness and the American criminal justice system.