In June 1902 a jury in Barnstable, Massachusetts, needed about 27 minutes to decide that Jane Toppan, a private nurse who was soon reported to have confessed to 31 killings, was not guilty by reason of insanity. Eighty-eight years later, in Rochester, New York, a jury spent six and a half hours on the case of Arthur Shawcross, listened to videotapes of him speaking in a woman’s voice under hypnosis, and concluded that he was not insane at all. Between those verdicts lies most of what American and Canadian courts have said about madness and repeated murder.
The defense is raised far less often than the public imagines, and in multiple killing cases it has usually lost. When it has won, the winner has seldom walked free. Toppan never left the state hospital. A man acquitted on that ground in Ontario in 1978 was committed to a maximum-security institution. A man acquitted in Washington in 1994 was still asking, more than twenty years later, for permission to spend a single day outside the hospital walls. The verdict trades a prison for a ward, and in practice the ward can hold a person longer.
What follows are ten cases. In four, the defense succeeded, at least for a time. In six, juries, judges or the defendants themselves abandoned it.
A verdict of not guilty by reason of insanity is not a conviction. It records that the accused did the act charged and cannot be held criminally responsible for it. The tests differ from place to place and from decade to decade, but they circle the same question: whether a mental disease left the accused unable to understand what he was doing, or unable to understand that it was wrong. Wisconsin in 1992 added a second branch, whether the disease left him unable to make himself obey the law. Canada abandoned the word insanity altogether after a 1991 decision of its Supreme Court, and now speaks of a person being not criminally responsible on account of mental disorder.
Sickness alone has never been enough. In several of the cases below, the experts on both sides agreed that the defendant was mentally ill, and the jury convicted anyway, because illness and legal insanity are separate questions. The courts have said so repeatedly, and juries have taken the point.
She was born Honora Kelley in Boston to Irish immigrant parents and, as a child, was placed with a Lowell family as a bound girl, never adopted; Lowell knew her as Jennie Toppan. She trained as a nurse in Cambridge and built a practice among families who trusted her. In the summer of 1901 she was with the Davis family of Lowell at their cottage in Cataumet, a village in the town of Bourne on Cape Cod. Within weeks the mother, both married daughters and the father were dead. She was arrested at Amherst, New Hampshire, on October 29, 1901, and a Barnstable County grand jury indicted her for three of the deaths.
Her sanity was examined before trial. The Lowell Historical Society records that three physicians, Henry R. Stedman, George Jelly and Hosea Quinby, examined her in March 1902 and judged her insane. The Commonwealth went to trial anyway, on the indictment for the death of Mary D. Gibbs alone, so that the question would be settled in open court. The trial at Barnstable on June 23, 1902, lasted about eight hours. The homicide went uncontested, the medical testimony agreed, and the jury returned its verdict of not guilty by reason of insanity. She was committed to the Taunton Insane Hospital for the rest of her life.
The number 31 dates from the period of her evaluation, Boston Magazine reports, and it was never tested in court. Neither were the doubts. After the trial, the magazine reports, she told a reporter that she had meant to be judged insane so that she might one day be released. The Lowell Historical Society names a member of one bereaved family, Oramel Brigham, and a Lowell physician, W. H. Lathrop, among those who believed she had never been insane.
If the plan was release, it failed. At Taunton, the Lowell Historical Society says, she came to fear that she was being poisoned, often refused food and declined. She died at the hospital in August 1938, at 81 by Boston Magazine’s account. The day itself is disputed: the Lowell Historical Society gives August 22, the West End Museum August 18.
For years nobody in Guelph or London, Ontario, knew that a series of deaths belonged together. GuelphToday lists four that Johnson later admitted and that had been recorded as something else entirely. Mary Hicks, 20, of London, in October 1973, was thought to have reacted to a prescription drug. Alice Ralston, 42, of Guelph, a month later, was put down to hardening of the arteries. Eleanor Hartwick, 27, of London, in March 1974, was believed to have reacted to medication. Doris Brown, 43, of Guelph, in August 1974, was recorded as pulmonary edema. None was reported to police as a crime.
Diane Beitz, 26, a Guelph woman who had become engaged the day before, died on December 31, 1974, and her case stayed open for three years. Louella George, 23, was killed in London in April 1977, and Donna Veldboom, 22, about three months later. Within two weeks of Veldboom’s death the police arrested Johnson, a tenant in her building, in London. He was 30. GuelphToday reports that he confessed to the three deaths and to a number of sexual assaults, and then named the four women whose deaths had passed as natural. Three women he had assaulted survived and identified him.
Before any of this came to light he had been a patient at a psychiatric hospital in London. In January 1978 he was tried for the murders of Beitz, George and Veldboom and acquitted by reason of insanity. The four deaths he admitted were never tried.
The verdict belongs to a regime that no longer exists. CBC News, reviewing earlier Canadian cases in 2024, noted that men such as Johnson were acquitted by reason of insanity in an earlier era and that the system was replaced after the 1991 decision. A Toronto lawyer told CBC that people with a similar profile today would probably not be held not criminally responsible, in part because they are often diagnosed with psychopathy or severe antisocial personality disorder. The forensic psychiatrist John Bradford, who said he had evaluated Johnson, told CBC that Johnson had been assessed in a different era and had no major mental illness. The verdict stands all the same. In law Johnson has never been convicted of anything.
The strangest insanity acquittal in this group was the one nobody contested. Between 1967 and 1971 the deaths of five young Black women came to light in Stamford, Connecticut: Rosell Rush, Donna Roberts, Gloria Kahn, Gail Thompson and Alma Henry. In February 1972 Benjamin F. Miller Jr., a white postal worker who called himself an ordained minister and preached in public in the city, was involuntarily committed to Fairfield Hills State Hospital with a diagnosis of chronic undifferentiated schizophrenia. There, medicated and at times on suicide watch, he confessed. He was arrested on March 17, 1972, and indicted on five counts of murder in May. He soon told his public defender that the confessions were false.
The State’s Attorney, Joseph T. Gormley Jr., offered a bargain. If Miller pleaded not guilty by reason of insanity, the state would present only a bare case. His lawyer, Herbert J. Bundock, believed the confessions held details only the killer could know, and he took it. In January 1973 two counts were dropped, and a panel of three Superior Court judges heard the other three in a single day. The hospital psychiatrist and a court-appointed psychiatrist testified for the defense; the prosecutor and the public defender both urged the panel to accept it. After a short recess the panel returned verdicts of not guilty by reason of insanity on all three counts. In March 1973 Miller was committed for up to 25 years.
What the defense never saw was the file on another man, identified in the federal record as R.L., who was arrested in Stamford in July 1972 over an assault on a woman in the same part of the city. According to the federal appeals court, detectives' reports tied him to at least four of the five women, and those reports went to the State’s Attorney and no further. Connecticut’s own courts rejected Miller’s habeas petition in 1983 and 1985.
On May 20, 1988, the United States Court of Appeals for the Second Circuit reversed, in an opinion by Judge Amalya Kearse. It held that the duty to disclose favorable evidence applies to an insanity plea just as it does to a guilty plea, because an insanity plea also gives up the protections of a full trial, and it held that the withheld material undermined confidence both in Miller’s choice not to contest the charges and in the finding that he had done the acts at all. The Supreme Court declined to hear the state’s appeal that October. Connecticut did not retry him. On May 8, 1989, the charges were dismissed, and Miller, by then unable to live on his own, went straight back into a mental institution of his own accord. The National Registry of Exonerations lists the case as an exoneration and names false confession among its causes.
In Miller’s case the insanity verdict did not shield a guilty man. It spared the state the work of proving that he was guilty.
For eight weeks in early 1993, from February 23 to April 19, people in Columbia Heights and Mount Pleasant in Northwest Washington were afraid to go out after dark. Fourteen shootings left four people dead and five wounded, the AFRO reported. Among the dead were Elizabeth Hutson, 28, known as Bessie, killed on March 23, and Nello Hughes, 61, killed on April 19. That afternoon an off-duty officer, Kenneth Stewart, arrested James E. Swann Jr., 29, a part-time security guard from Iselin, New Jersey.
The case never reached a jury. Swann told doctors of demons and spirits, Malcolm X among them, and of voices urging him on; the Associated Press reported that the voices told him to avenge the death of Malcolm X. He was diagnosed with schizophrenia and narcissistic personality disorder. In 1994 he was judged not guilty by reason of insanity on 32 charges and committed to St. Elizabeths Hospital. William O. Ritchie, who commanded the police department’s criminal investigations division, told the AFRO that he knew from the day of the arrest that the case would not be tried. "I looked him in the eye and I knew that he was dancing to a different tune," he said.
The hospital did not become a revolving door. In February 2011, at 46, Swann asked Judge Fred B. Ugast of D.C. Superior Court for a 12-hour furlough to spend a day with his father. Prosecutors, government experts and the hospital’s own experts opposed it. Ugast’s ruling recorded that by 2003 medication and therapy had largely eliminated his psychotic symptoms, but that his schizophrenia was only in partial remission and that he still showed no sign of remorse. "There are no conditions that could be set that would eliminate the risk of harm to Mr. Swann" if he were released, the judge wrote, and he refused.
A motion for conditional release followed in December 2017. The hospital opposed that too, telling the court in February 2018 that Swann still left the grounds only in the company of two staff members. Chief Judge Robert Morin set hearings for September 2018. As of February 2018 Swann was held at St. Elizabeths, a quarter of a century after the shootings, under a verdict that was never a conviction.
Edmund Kemper had already been through the hospital once. In 1964, at 15, he killed his paternal grandparents in Madera County, California. Because of his age the case went to juvenile court, not to an adult prosecution, and he was sent to Atascadero State Hospital, the state’s maximum-security psychiatric institution. Lookout Santa Cruz reported in 2024 that he was released to his mother’s care on his 21st birthday.
Between 1972 and 1973 he killed eight people in and around Santa Cruz County, among them six young women and girls who were students, his mother and her friend. He was arrested in Pueblo, Colorado, in April 1973 after confessing by telephone, and on April 30 he was arraigned in Santa Cruz on eight counts of murder. He pleaded not guilty by reason of insanity. The court-appointed psychiatrists judged him sane, United Press International later recalled. Kemper testified at his own trial and told the jury that he had wanted the young women "for myself."
On November 8, 1973, the jury convicted him on all eight counts of first-degree murder. The insanity plea had failed against a man who had spent years in a state hospital and had been released from it as fit to rejoin his mother. He was sentenced to life. In July 2024, at 75, he was held at the California Medical Facility in Vacaville, and a parole panel denied him release again; the next hearing was set for 2031.
Manuel Pardo had worn a badge, first with the Florida Highway Patrol and then with the police in Sweetwater, a small city in Dade County. In 1986 he and an accomplice killed nine people in five episodes between January and April. His lawyer, Ronald Guralnick, looked at the state’s evidence, judged it overwhelming and decided that insanity was the only defense left. On March 22, 1988, about two weeks before trial, he gave notice.
Three court-appointed experts judged Pardo competent and sane. The defense psychologist, Syvil Marquit, testified that he was legally insane, but, as the Supreme Court of Florida later summarized it, also said that Pardo was psychotic and knew that murder was illegal and wrong. Guralnick then made a calculated gamble. Instead of separate trials for each episode, he agreed to try all nine killings together, reasoning, as he explained years later, that if one jury accepted insanity his client would be "a total winner," while separate trials offered about the odds of a lottery ticket.
His client wrecked the plan. Over Guralnick’s objection, Pardo took the stand, admitted that he had intentionally killed all nine, told the jury that his victims had no right to live, and said that he was not insane. On April 15, 1988, the jury convicted him on every count. In the penalty phase he testified again, again against his lawyer’s advice, and asked for death rather than life in prison. The jury recommended death on all nine counts, and the judge imposed it.
The Supreme Court of Florida affirmed on May 31, 1990. It held that the state had offered competent, substantial evidence of sanity and that the trial court was not obliged to accept Pardo’s self-serving account of his motives as proof that he could not appreciate the wrongfulness of what he did. In 2006 the same court held that consolidating the trials was a reasonable strategy for an insanity defense, and in 2009 the Eleventh Circuit agreed. Pardo was executed at Florida State Prison in Starke on December 11, 2012, and pronounced dead at 7:47 p.m. He was 56.
No case in American history did more to make prosecutors suspicious of a defendant under hypnosis. On January 12, 1979, Kenneth Bianchi, a security guard, was arrested in Bellingham, Washington, and charged with the murders of two young women, Karen Mandic and Diane Wilder. Los Angeles detectives had already linked him to a series of killings of women and girls in their county in 1977 and 1978. In March 1979 he changed his plea to not guilty by reason of insanity. His lawyer said he had no memory of the killings and that three psychiatrists had diagnosed severe multiple personality disorder. The prosecutor gave notice that he would seek death.
On March 21, 1979, a defense psychologist, John G. Watkins, hypnotized Bianchi, and a personality calling itself Steve appeared and claimed the killings. The prosecution called Martin Orne, a University of Pennsylvania psychiatrist and an authority on hypnosis. Orne remarked to Bianchi that it was "pretty rare for there to be two" personalities, and a third, Billy, soon appeared. He suggested that Bianchi’s lawyer was sitting in the room when he was not, and Bianchi rose, shook hands with the empty air and asked whether the examiner could see the man too. Orne and his co-authors wrote in 1984 that they had never seen a deeply hypnotized subject behave that way. Steve, they added, had grown more aggressive and profane over about two months, a change "incompatible with the pre-existence of a distinct, well-integrated alter personality," and nobody from Bianchi’s earlier life had seen any trace of other selves. Even the name Steve Walker belonged to a real psychologist whose diplomas Bianchi had once used. Orne’s conclusion was blunt: "Mr. Bianchi was simulating a multiple personality."
The court’s six-member panel of experts split evenly, two for each view and two undecided, HistoryLink reports. Then the case ended without a verdict on sanity at all. On October 19, 1979, Judge Jack Kurtz held Bianchi competent, and Bianchi withdrew the insanity plea and pleaded guilty to both Bellingham murders in exchange for the state dropping its death notice. He received two consecutive life terms. Three days later, in Los Angeles, he pleaded guilty to five counts of murder, with other charges, and agreed to testify against his cousin.
He has since claimed that hypnosis planted false memories and produced the confessions. The Ninth Circuit rejected that argument in 1994, observing that it was "not clear that he was ever hypnotized" and that he had pleaded guilty to avoid the death penalty. Under the legal name Anthony D’Amato, he was held at the Washington State Penitentiary in Walla Walla as of October 22, 2026, after a Washington board declined to release him in July 2025.
Arthur Shawcross had escaped a murder trial once before by a different door. In 1972, in Watertown, New York, he pleaded guilty to manslaughter in the first degree in the death of an eight-year-old girl. His lawyer, Paul J. Dierdorf, later told the Watertown Daily Times that the manslaughter law then covered killings committed under extreme emotional disturbance, and that juries had recently returned that kind of verdict. Shawcross was sentenced to up to 25 years and paroled on April 30, 1987.
By January 1990 he was charged in Monroe County with the murders of ten women in and around Rochester. He did not contest that he had killed them. His defense was insanity, built on claims of brain damage, childhood abuse and his service in Vietnam, and its chief witness was the psychiatrist Dorothy Otnow Lewis. The jury watched videotapes of her interviews with him under hypnosis, in which his voice rose to a woman’s pitch and he said his mother’s voice had told him to kill. The prosecution’s psychiatrist, Park Dietz, testified that Shawcross had denied to him hearing voices or having other personalities, and that he was faking mental illness to stay out of prison. Lewis lost her composure under cross-examination. Shawcross did not testify.
On December 13, 1990, after about six and a half hours, the jury convicted him of ten counts of second-degree murder. The foreman said the jurors had decided that Shawcross "wasn’t insane," the Deseret News reported. Each count carried 25 years to life.
On appeal he argued, among other things, that his expert had failed him. The Appellate Division, Fourth Department, unanimously disagreed on April 14, 1993. Lewis was well qualified and had assisted the defense, it held, and "her loss of composure under vigorous cross-examination did not rise to the level of incompetent psychiatric assistance." Shawcross died in state custody on November 10, 2008, at 63, of a pulmonary embolism. The New York State Commission of Correction later concluded that his medical care had been grossly negligent.
Jeffrey Dahmer never denied what he had done. Charged in Milwaukee with fifteen counts of first-degree intentional homicide, he changed his plea on January 13, 1992, to guilty but insane, so the trial that opened before Judge Laurence C. Gram Jr. on January 30 concerned only one question. Under Wisconsin law the defense had to prove that he suffered from a mental disease and that, because of it, he either could not appreciate the wrongfulness of his conduct or could not conform his conduct to the law.
The defense experts described disorders they called mental diseases that drove his behavior. The prosecution’s experts, including Park Dietz, described the killings as planned and deliberate, the work of a man who took pains to avoid detection, and therefore of a man in control. The jurors heard both, and on Saturday, February 15, 1992, they held him sane on every count, by ten votes to two each time, the minimum Wisconsin required, United Press International reported. Because ten jurors decided there was no mental disease, they never reached the question of self-control.
Two days later, before Judge Gram sentenced him to fifteen consecutive life terms, Dahmer spoke for the first time. He said he took all the blame and that he now believed he had been sick. Wisconsin had no death penalty. On November 28, 1994, another prisoner killed him at the Columbia Correctional Institution in Portage. He was 34.
The last case tested the defense twice, once to escape conviction and once to escape execution. Angel Maturino Resendiz surrendered in July 1999 and was tried in Houston in May 2000 for the capital murder of Dr. Claudia Benton, 39, a physician from West University Place, Texas. His lawyer did not dispute that he had killed her; he told the jury that Resendiz had killed nine people in three states and argued that he was insane.
Defense experts testified to chronic paranoid schizophrenia, with what Amnesty International later described as a delusion that he was an angel of God. Prosecution experts did not deny that he was mentally ill and saw signs of brain damage, but said he knew right from wrong. Judge William Harmon refused to let the defense show the jury photographs from the other killings, which the defense said would display the depth of the illness. On May 18, 2000, after about ten hours, the jury convicted him of capital murder. He then told his lawyers not to fight the punishment phase, and the jury voted for death.
The Texas Court of Criminal Appeals affirmed by seven votes to two on May 21, 2003. The majority held that the photographs risked confusing abnormal behavior with legal insanity. Judge Paul Womack, joined by Judge Cheryl Johnson, dissented and would have ordered a new trial, finding the pictures relevant to his sanity. The court also held that the words "know" and "wrong" in the Texas insanity statute needed no definition for jurors.
Six years later the question changed. The Constitution forbids executing a prisoner who cannot understand why he is to die, and at a three-day hearing in Houston in June 2006 the experts divided evenly, three saying he was incompetent and three saying he was not. Defense psychiatrists said he believed he would survive the injection and return three days later. Judge Harmon held that Resendiz understood he had been convicted of capital murder, that his execution was imminent and why. On June 27, 2006, the Fifth Circuit refused to intervene, noting that his mental illness had been known since he pleaded insanity at trial, and the Supreme Court denied five applications for a stay. He was executed at the Huntsville Unit that evening and pronounced dead at 8:05 p.m.
The four defenses that succeeded have little in common with the six that failed except the diagnoses. Toppan, Johnson and Swann were judged insane by experts on both sides, or with no serious contest; Miller was acquitted on that ground because both lawyers asked for it. In the failures, the defendants' own words did much of the damage. Kemper told jurors what he had wanted. Pardo told them he was not insane. Dietz in Rochester and in Milwaukee pointed to planning and concealment as proof of control, and juries accepted the inference. Bianchi’s alternate selves dissolved under one expert’s tests before any jury heard them.
The successful verdicts were not, in any ordinary sense, lenient. Toppan died in the hospital at 81. Swann was still confined in 2018. Johnson was committed in 1978, and the psychiatrist who examined him later said he had no major mental illness. Miller’s verdict, the one that came easiest, rested on confessions taken on a locked ward and on a file the defense never saw, and it took a federal court fifteen years to set aside.
The insanity verdict is meant to separate the sick from the guilty. In these ten cases it separated something narrower: the defendants whom the experts, the lawyers and the jurors could agree had not known what they were doing, from those who, however ill, plainly had.
• October 29, 1901: Jane Toppan arrested at Amherst, New Hampshire.
• June 23, 1902: Toppan tried at Barnstable for the death of Mary D. Gibbs; not guilty by reason of insanity; committed to the Taunton hospital for life.
• 1964: Edmund Kemper, 15, kills his grandparents; juvenile court commits him to the state system, and he is held at Atascadero State Hospital.
• March 17, 1972: Benjamin Miller arrested in Stamford, Connecticut, after confessing at Fairfield Hills State Hospital.
• 1972: Arthur Shawcross pleads guilty to manslaughter in the first degree in Watertown, New York.
• January 1973: a three-judge panel returns verdicts of not guilty by reason of insanity on three counts against Miller.
• November 8, 1973: Kemper convicted of eight counts of first-degree murder in Santa Cruz County.
• January 1978: Russell Maurice Johnson tried for three murders in Ontario; not guilty by reason of insanity.
• January 12, 1979: Kenneth Bianchi arrested in Bellingham, Washington.
• October 19, 1979: Bianchi withdraws the insanity plea and pleads guilty to two murders in Bellingham.
• April 15, 1988: Manuel Pardo convicted of nine counts of first-degree murder in Dade County, Florida.
• May 20, 1988: the Second Circuit grants Miller habeas relief.
• May 8, 1989: charges against Miller dismissed.
• December 13, 1990: Shawcross convicted of ten counts of second-degree murder in Monroe County, New York.
• February 15, 1992: a Milwaukee jury holds Jeffrey Dahmer sane on fifteen counts.
• April 19, 1993: James Swann arrested in Northwest Washington.
• 1994: Swann judged not guilty by reason of insanity on 32 charges; committed to St. Elizabeths Hospital.
• November 28, 1994: Dahmer killed at Columbia Correctional Institution.
• May 18, 2000: Angel Maturino Resendiz convicted of capital murder in Houston.
• May 21, 2003: Texas Court of Criminal Appeals affirms Resendiz’s conviction, seven to two.
• June 27, 2006: Resendiz executed at Huntsville after being held competent to be executed.
• November 10, 2008: Shawcross dies in custody.
• February 25, 2011: Judge Ugast denies Swann a 12-hour furlough.
• December 11, 2012: Pardo executed at Starke, Florida.
• February 7, 2018: Swann’s motion for conditional release argued; hearings set for September 2018.
• July 9, 2024: Kemper denied parole.
• October 22, 2026: Bianchi, as Anthony D’Amato, listed at the Washington State Penitentiary.