On the evening of December 21, 1924, in a small Silesian market town, a case that had begun at lunchtime was already over. A man named Karl Denke, arrested that afternoon after a traveling journeyman reported him to police, had died in custody. No charge was ever laid. Everything that came afterward, the laboratory tests, the lists of the missing, the figure of 20 dead that investigators settled on and the larger figures that journalists have floated since, rests on newspaper reports and one Polish historian’s reading of them.
That is a fair picture of the period. Between the end of the First World War and the start of the Second, serial offenders were identified and tried in Hanover, Düsseldorf, Moscow, Winnipeg, Cincinnati, Vienna, La Spezia and the Kanto plain of Japan, yet the word for what they were did not yet exist in most of those languages. Detectives had fingerprints, medical examiners and the telegraph. They did not have a national database, a shared definition of a series, or the habit of comparing a death in one town with a death in the next. Courts had the death penalty, a settled idea of criminal responsibility and juries that wanted a name for the dead. The press had circulation to win. The nine cases below show what that combination could achieve, and what it let slip.
Between September 1918 and June 1924, at least 24 boys and young men, aged 10 to 22, were reported missing in Hanover after meeting Fritz Haarmann. Most were teenagers. Many were runaways or travelers passing through the city’s main railway station, in a city of roughly 450,000 people that Theodor Lessing, the philosopher who later wrote the fullest account of the case, described as a center of black-market trade. In 1923 alone almost 600 people were reported missing there, most of them boys between 14 and 18. Nobody was positioned to see 24 of them as a pattern.
Haarmann, born in Hanover on October 25, 1879, was a petty criminal with a record of prison terms who dealt in secondhand clothing and meat. From 1918 he was also an informer for the Hanover criminal police. The Lower Saxony State Archive says that the police pressured him into the work and that it was the reason earlier suspicions went unexamined and missing-person reports were handled slowly. He carried an official pass that let him move through the station’s waiting rooms, and boys who met him there took him for a plainclothes detective.
The first failure was recorded in October 1918. Parents of a missing 17-year-old, Friedel Rothe, traced a man who had been seen with their son to a set of rented rooms, and an officer went there at night. He took away Haarmann and another boy, and Haarmann was later sentenced to nine months for an offense against that boy. The officer did not search the rooms; asked why, he said he had had no orders to. When the case reopened in 1924, Haarmann admitted that Rothe was already dead by the night of that visit. It is the plainest single example of a failure that ran through the whole case. In February 1923 a second warning was set aside. Two women from Haarmann’s circle took their suspicions to the police, a police doctor dismissed what they brought without a proper examination, and a search of the rooms turned up nothing.
The killings came to light in 1924. Haarmann was arrested in Hanover on June 22 on a complaint about a teenager, and was held in the court prison from the next day. He confessed. The state archive’s count is 21 killings confessed; the city of Hanover’s summary says nine confessed, twelve more called possible and six denied. His own estimate, as Lessing recorded it, was "it could be thirty, it could be forty; I don’t know." The Schwurgericht at the Landgericht Hannover heard the case over 14 hearing days between December 4 and 19, 1924. Haarmann was charged with 27 murders, convicted of 24 and acquitted of three. His companion Hans Grans, tried with him for incitement and aiding, was sentenced to death; after a retrial in 1926 the sentence became 12 years' penitentiary for aiding two murders. He was released in January 1946 and died in 1975. Haarmann accepted the verdict and was beheaded by guillotine in the prison yard at 6 a.m. on April 15, 1925. His head was kept in Göttingen until the university cremated it, quietly, in 2014.
Lessing attended the trial, argued in print that Haarmann’s police connections had both opened doors for him and shielded him for years, and was barred from the courtroom. He was later driven from his university post and, in 1933, was killed by Nazis outside Germany. The forensic psychiatrist Christine Pozsár, who studied the 1924 psychiatric interviews in the 1990s, concluded that the assessment of Haarmann had ignored what he said of his childhood. The director of the Lower Saxony Police Museum says that much suggests there were more victims than the court convicted him of.
In 1929 Düsseldorf lived through a series of killings and assaults by someone nobody could name. The police were accused of failing. A leading Berlin detective, Ernst Gennat, came to help, and, the legal historian Martin Rath writes, coined the German word *Serienmörder* in connection with the case. More than a hundred clairvoyants offered their services, and the physician A. A. Friedländer, writing in the weekly *Die Umschau* a month after the trial, reported that every one of them failed.
The man was Peter Kürten, born in Mülheim am Rhein on May 26, 1883, the third of 13 children, according to Britannica. By his last arrest he had been sentenced to prison nearly 30 times. The historian Michael Sauter notes that from 1903 to 1921 he was in effect in the state’s custody, with short spells of freedom that ended in new arrests. Married in 1921 and living in Düsseldorf from 1925, he presented himself to neighbors and employers as a steady working man. Düsseldorf’s population had grown from about 175,000 in 1895 to more than 430,000 in 1925, and Sauter argues that the larger city gave him anonymity.
He was arrested in Düsseldorf in 1930. According to the German Press Agency’s report on a file that surfaced in 2023, a woman who survived one of his assaults pointed investigators to his address, and he had by then confessed to his wife. The confession that followed was detailed. He took it back at one point, then returned to it, and he was sent to the provincial asylum at Bedburg-Hau for examination. Karl Berg and the other experts held him fully responsible for his acts, which matched the test then set out in paragraph 51 of the criminal code. Friedländer wrote that they agreed with a rare unanimity.
The trial opened on April 13, 1931, before the Schwurgericht at the Landgericht Düsseldorf, in the tower hall of a former cavalry barracks in Derendorf, and ran until April 22. Britannica describes a national event that drew academic observers. Part of the hearing was closed to the public. Kürten was convicted of nine murders and seven attempted murders. The first murder tried was that of Christine Klein, a girl of nine, killed in Mülheim in 1913 and unsolved until his confession in 1930. The others were committed in Düsseldorf in 1929. He was sentenced to death for each of the nine murders and to a combined 15 years' penal servitude for the attempts. A claim he made, that he had drowned two boys in the Rhine as a child, was left out of the judgment; Rath explains that criminal responsibility began at 12 and that there was no evidence. The Prussian State Ministry rejected a clemency petition at noon on June 30, and he was guillotined in the Klingelpütz prison in Cologne at about 6 a.m. on July 2, 1931.
Letters in the investigating judge’s file, which turned up in 2023, suggest he did not expect to be executed. Shortly before he was moved back from Bedburg to Düsseldorf he asked for a freshly painted cell on the sunny side. The state archive of North Rhine-Westphalia now holds 223 court files on the case.
Münsterberg, now Ziębice in southwestern Poland, was a German market town of about 9,000 people in Lower Silesia in the 1920s, 50 kilometers from Breslau. The historian Lucyna Biały of the University of Wrocław wrote the first scholarly account of Karl Denke in 2001 and reconstructed it from surviving issues of the local and regional press. The man in her account was calm, orderly, pedantic and devout. He carried the cross in funeral processions, gave food and a night’s lodging to men traveling for work during the hyperinflation years, and was known in the town as Father Denke.
On Sunday, December 21, 1924, a journeyman out of work, begging in the town, got away from Denke’s lodgings and reported him to police at about 1 p.m. The police did not believe him at first. A commissioner dismissed his account, and it was the journeyman, a traveler without papers, who was locked up, though he was given medical treatment. The seriousness of his injury outweighed the reputation of the man he accused, and police went to Denke’s house and arrested him. At about 9:30 that evening he was reported dead in his cell; local newspapers described a suicide. Biały takes the time from the local press; the Czech broadcaster CNN Prima gives about 9 p.m. Denke left no statement. The journeyman was tried on January 15, 1925, as a vagrant under Section 361 of the criminal code and sentenced to 10 days in jail.
On December 24, officers went to Denke’s rooms to secure his belongings at the request of his relatives, not to search for evidence. What they recorded led to a criminal investigation. Identity papers belonging to other people turned up in quantity. A forensic laboratory in Breslau examined material from the house and, Biały writes, reported it human tissue from three people. The earliest newspaper reports spoke of five men, and the figures have never been reconciled.
Investigators attributed the deaths of at least 20 people to Denke, according to Biały and the City of Wrocław, most of them men traveling for work, whose trades she lists: carpenter, tailors, bakers, a weaver, a locksmith. Later estimates by researchers and the press run to 30 or 40. None of these deaths was ever proved in court, and Denke was never charged. Biały writes that the case was soon forgotten.
In the early 1920s, as Moscow recovered from revolution, civil war and famine, men began to be reported missing from the city’s horse market. Most were peasants from outside the capital with cash to buy a horse. The Moscow criminal investigation department, less than five years old, did not see the deaths as a series at first; the broadcaster Alexey Kuznetsov dated that recognition to early 1923. In May 1923 it arrested a cab driver who called himself Vasily Ivanovich Komarov. His real name was Vasily Terentyevich Petrov, born in 1877 or 1878 in Vitebsk Governorate, a former Red Army platoon commander who had taken a new surname after being captured by White forces in 1919.
The count is the first disputed point. Komarov claimed 33 killings. Outlets give 29 as the number charged or proven. Mikhail Bulgakov, who covered the trial for the Berlin paper *Nakanune*, wrote that investigators had established 22 dead and identified seven. The only victim whose name has been reported is Ivan Lapin, a peasant from the Moscow region and father of four. Asked about motive, Komarov gave answers that shifted from telling to telling. One reported line is that his wife liked to eat well and he liked to drink, and the horse fed him but did not keep him in drink. The plain motive, historians agree, was robbery.
He was tried with his wife, Sofia, at the Polytechnic Museum in June 1923, in a crowded hall, with foreign correspondents and newsreel cameras present. Her part is the most disputed point of the case. Moskvich Mag reports that she helped clean up afterward; Diletant quotes Komarov telling her they would have to get used to it; Bulgakov, watching her in court, saw a meek and dull woman who had been sent out of the house with the children. Kuznetsov thought her death sentence surprising and suggested that public anger on the judges might explain it. Both were sentenced to death and shot in 1923; one outlet dates the sentence’s execution to June 18. Their children were placed in state care.
Earle Nelson was hanged in Winnipeg on January 13, 1928, for the murder of Emily Patterson, a 27-year-old woman. That conviction is the only one in his record. Police in the United States and Canada had linked him to a long series of deaths that began in San Francisco in February 1926 and ran east across the continent to Manitoba. The Canadian Press, looking back in 1967, wrote that police in both countries closed the files on 22 cases when he died. Most of the dead were women who rented rooms. Other counts differ: 24 American deaths plus two in Winnipeg, according to the Winnipeg Police Museum; at least 21 women and a baby, possibly more than 30, in a 2013 account; up to 34 in the work of the University of Manitoba law professor Alvin Esau, who has written two books on the case.
He never confessed. The Manitoba Historical Society notes that the link between Nelson and the American deaths was purely circumstantial. The record that a court tested is narrower: one Winnipeg jury, one victim, and a defense of insanity that the jury rejected in November 1927. The girl whose death police also attributed to him in Winnipeg, Lola Cowan, 14 by the Society’s count and 13 by another, was never the subject of a trial.
Nelson was born in San Francisco, with years given as 1898 to 1928. Esau, who obtained the Manitoba Attorney General’s files, told the university’s news service in 2022 that the familiar stories of a fanatically religious upbringing have no evidence behind them and are myths endlessly repeated. The manhunt that ended with his arrest near Wakopa, Manitoba, on June 15, 1927, spread across three provinces; the Society calls it Canada’s largest. The Canadian Press described a trail some 7,000 miles long over 17 months, and no single inquiry in the United States had joined it up. It ended in a rural Manitoba hamlet.
Anna Marie Hahn was 31 when a Cincinnati jury convicted her, in November 1937, of the murder of Jacob Wagner, a 78-year-old German-American man, by poisoning. Time magazine described her as a Bavarian immigrant who had taken about $50,000 from elderly friends over eight years, much of it to bet on horses. She had arrived in the United States in 1929 at 23. The jury of eleven women and one man deliberated three hours and returned its verdict without a recommendation of mercy, which meant death. The Supreme Court of Ohio’s history page says no such verdict had been returned before in Hamilton County.
The inquiry began far from Cincinnati. In August 1937 a hotel in Colorado Springs reported $305 in missing rings; an elderly man who had visited the hotel with Hahn died the next day, and a theft complaint became a death inquiry. By August 19 she was under indictment for first-degree murder in two deaths and had pleaded innocent. The prosecutor, Dudley Miller, told the Associated Press that at least eleven deaths were being examined and called it "the biggest mass murder in this country." Only the Wagner death was put to a jury. The Supreme Court of Ohio says the evidence showed that she had killed three more men and disabled another. The second indictment was never tried.
Her defense took an unusual line: according to Time, her lawyers conceded theft, adultery and forgery to argue she had poisoned no one. Judge Charles S. Bell sentenced her to death. She was held at the Ohio Penitentiary in Columbus, the only woman among about 4,200 prisoners, and was electrocuted on December 7, 1938, sixteen months after her arrest. The author Diana Britt Franklin, who spent five years studying her, said in 2006 that nobody had expected a death verdict from a jury of eleven women.
Martha Marek was sentenced to death in Vienna in May 1938, two months after Germany annexed Austria. Time, reporting the verdict in its issue of May 30, said the court had ruled that she killed her small daughter, an aunt and the family seamstress to collect insurance. The Austrian magazine *News* adds her husband, who fell ill and died in 1932, and reports that police established that all four dead had been poisoned. Whether the husband’s death formed part of the verdict has not been reported, and accounts of the poison differ.
Her story reached the courts twice. In the 1920s she and her husband faced proceedings over a claim on his accident insurance after he lost a leg. Time says the couple collected $42,875; the biographical reference *Women in World History* says the claim failed and that both were convicted of bribery and served four months. The two outcomes cannot both be right. In the 1930s a run of deaths among people close to her brought her gifts of money, an inheritance and a life insurance payout, and she was treated as a grieving widow and mother. Suspicion came only when the seamstress’s son went to the police. *Women in World History* adds that an insurance claim over paintings reported stolen drew a detective’s attention to her.
She maintained her innocence. Time described the presiding judge as a Nazi. She was beheaded by guillotine at the Vienna criminal court later in 1938; Capital Punishment UK gives the date as December 6 and thinks she may have been the last woman put to death in Austria for murder after an ordinary jury trial. The same court became one of the main places of execution in Nazi-ruled Austria, where an estimated 100 women were put to death by German executioners in Vienna and Graz between 1938 and 1945.
Cesare Serviatti was convicted in July 1933 of murdering three women he had met through newspaper marriage advertisements. The killings spread across four years: a widow, Pasqua Bartolini, in La Spezia in 1928; Beatrice Margarucci, called Bice, in Rome in 1930; and Paolina Gorietti, about 40, in La Spezia in November 1932. A former hospital nurse and butcher from Rome, he was short and stocky, with a large mustache. Witnesses at trial described a normal man. The Italian press compared him with the French Landru and called him the butcher of Rome.
The first two women’s deaths drew no inquiry. No relative reported Bartolini missing, and the case surfaced only after Serviatti’s arrest more than four years later. Margarucci’s death was handled in 1930 by the same commissioner who later worked the 1932 case, according to Città della Spezia, without identifying anyone. The third was different, because Gorietti had a friend. In mid-November 1932 an unidentified woman was reported dead in La Spezia, and police in Naples, Rome and La Spezia began working together. Witnesses at the railway station remembered a heavyset man of about fifty. About a hundred people were questioned without result. In early December Gorietti’s friend in Rome read the newspaper descriptions and went to the police. Gorietti had left Rome for La Spezia on November 4 to marry a man she had met through an advertisement, Cesare Serviatti, and the letters had stopped after November 11.
Serviatti was arrested in Rome in December 1932. Il Giornale gives December 9 in one account and December 13 in another. A medical report held that Gorietti had died of strangulation. His first account was self-defense; he later confessed to her death and to Margarucci’s, and he spoke of as many as five killings in all, though only three were charged. The accounts disagree about the officer who solved the case. One credits the commissioner Dosi, who coordinated the La Spezia inquiry; he was paid a fee of 1,000 lire, was paid again by a New York newspaper for a detailed report, and was later dismissed from the police.
He was tried summarily before the Corte d’Assise of La Spezia from June 14, 1933. On July 8 the court sentenced him to death for the Gorietti murder and to life imprisonment for the other two. King Victor Emmanuel III refused clemency, and Serviatti was shot by firing squad at Sarzana on October 13, 1933. His wife, investigated as a possible accomplice, was acquitted.
Sataro Fukiage was hanged at Ichigaya Prison in Tokyo on the morning of September 28, 1926. In 1906, at 17, he had been convicted of killing an 11-year-old girl in Kyoto and sentenced to life imprisonment, a sentence cut to 15 years because he had been a minor and because of an amnesty. He was released on March 18, 1922. In the summer of 1924 he was arrested and charged with killing six girls in the prefectures around Tokyo and in Nagano.
The writer Koike (小池新), who went back over the newspapers, police histories and memoirs for Bunshun Online in 2022, located little coverage of several of the killings when they happened. The Great Kanto Earthquake of September 1923 consumed the attention of the press and the police; the Toranomon Incident and the crown prince’s wedding followed. When the police did connect the cases, they did it by committee. Shortly before the arrest, detective chiefs of the Metropolitan Police and the Kanto prefectural forces met in Gunma and agreed to search for the suspect together on July 28 and 29, a form of coordination still unusual in Japan.
What they had was a photograph. The Jomo Shimbun reported that the Gunma police brought a picture taken at a party in Nagano in July 1923 and a scrap of handwriting. At a Tokyo police station a detective recognized the face as that of a laborer questioned the year before over an assault on a child at his workplace, and recalled that the man had begun to sign his statement with the character of a different surname before correcting himself. Fukiage was arrested in Tokyo at about 6 p.m. on July 28, 1924. Press accounts in the days after credited him with more than 20 killings, then 17, then 13. Koike doubts the larger figures and suggests that reporters attributed unsolved cases to him freely. In custody he confessed to killings for which other men had been tried, then withdrew the confessions in court.
The Maebashi District Court sentenced him to death on May 7, 1925, for three of the killings, two in Gunma and one in Nagano. The Tokyo Court of Appeal upheld the sentence on April 24, 1926, and his last appeal was dismissed on July 2. In his cell he wrote an autobiography of more than a thousand manuscript pages. One volume was printed, then banned.
A reader looking for the 1920s and 1930s in these nine cases will not find a single method or a single kind of offender. The defendants include a police informer, a man with nearly 30 prison sentences, a cab driver, a drifter, two women convicted of poisoning for money, a former hospital nurse and a laborer released from prison after 15 years. What they share is more administrative than psychological.
Police in the period could act on a name but struggled to act on a pattern. In Hanover the pattern was visible in the number of missing boys, and the one detective who visited the right address in 1918 had no orders to search. In Düsseldorf the Prussian police borrowed the best detective in Berlin and still waited on a survivor and a confession. In Moscow, Italy and Japan the breakthrough came from a witness, a friend or a photograph, not from the comparison of one death with another. Forensic science could identify human tissue, as in Breslau, and could not yet date or place most deaths. Newspapers filled the gap with numbers: 13, 17, 20 and more for Fukiage; 22 for Nelson; 40 for Denke.
The courts did something neater. They convicted for what they could prove and left the rest as attribution: a single jury in Winnipeg, one death out of two indicted in Cincinnati, three of six in Maebashi, 24 of 27 in Hanover. In Münsterberg the court never sat. Eight of the nine were executed; the numbers the public remembers still outrun the verdicts.
• 1906, September 24: an 11-year-old girl is killed in Kyoto; Fukiage is later sentenced to life imprisonment.
• 1913: Christine Klein, nine, is killed in Mülheim; unsolved until Kürten’s confession in 1930.
• 1918, September and October: Friedel Rothe, 17, goes missing in Hanover; an officer visits Haarmann’s rooms in October and does not search.
• 1921: Komarov sets up as a private cab driver in Moscow.
• 1923, February 12: the first of the 1923 killings tried against Haarmann takes place in Hanover.
• 1923, September 1: the Great Kanto Earthquake.
• 1924, June 22: Haarmann is arrested in Hanover.
• 1924, July 28: Fukiage is arrested in Tokyo.
• 1924, December 19: Haarmann is convicted of 24 murders.
• 1924, December 21: Denke is arrested in Münsterberg and dies in custody the same evening.
• 1925, April 15: Haarmann is guillotined in Hanover.
• 1926, February: killings attributed to Nelson begin in San Francisco.
• 1926, September 28: Fukiage is hanged.
• 1927, June 15: Nelson is arrested near Wakopa, Manitoba; convicted in November.
• 1928, January 13: Nelson is hanged in Winnipeg.
• 1929: the Düsseldorf series.
• 1931, April 22: Kürten is convicted; he is guillotined on July 2.
• 1932, December: Serviatti is arrested in Rome.
• 1933, July 8: Serviatti is sentenced; shot October 13.
• 1937, August: the Hahn inquiry opens in Colorado Springs and Cincinnati; she is convicted in November.
• 1938, May: Marek is sentenced to death in Vienna.
• 1938, December 7: Hahn is electrocuted.