In 1909 Landru attempted to swindle an affluent widow in the northern city of Lille by posing as a wealthy, single businessman and persuading her to hand over her savings in a pre-marital contract.

[11] In the winter of 1913–14, Landru executed easily the most successful swindle of his career, duping more than a dozen individuals into giving him a total of 35,600 francs to "invest" in building a fictitious automobile factory.

Taking his previous convictions into account, the court sentenced Landru to four years of hard labour followed by exile for life on the French Pacific island of New Caledonia.

She knew him at this stage as "Raymond Diard", an industrialist from northern France, who had promised to marry her and had persuaded her to give up her job making lingerie for a dress shop in Paris.

He did not begin to keep detailed notes in the carnet until the summer of 1916, and even then, statements by various witnesses proved beyond doubt that Landru did not record all his planned and impromptu encounters with women in the later years of the war.

Originally from Le Havre, Berthe Héon scraped a living as a cleaning woman and had suffered multiple bereavements, losing in turn her husband, her long-term lover, her two legitimate children and her beloved illegitimate daughter in childbirth.

[18] Anna Collomb was a clever, attractive widow who worked as a typist at an insurance company in Paris and had had a string of lovers since the death of her alcoholic, bankrupt husband a decade earlier.

Landru, alias Georges Frémyet, became "engaged" to Buisson immediately, but then put off their marriage for more than two years, pleading lost identity documents and long "business trips" abroad.

She was a devout Catholic, working as a dress shop assistant, who answered a lonely-hearts advertisement Landru placed in a conservative newspaper after deciding to divorce her estranged husband.

On account of her wide-brimmed hats, Annette Pascal was nicknamed "Mme Sombrero" by her neighbours on the street near the Père Lachaise cemetery where she lived and worked, making dresses for a Paris fashion house.

Pascal was divorced and childless, following the death of her only son in infancy, and was looking for a so-called "vieux monsieur" ("sugar daddy") in September 1916 when she spotted Landru's lonely-hearts advertisement in the Paris evening daily, La Presse.

[20] Born in Bordeaux, Marie-Thérèse Marchadier was a career prostitute and a familiar sight on the street outside her apartment on Paris's Rue Saint-Jacques, where she liked to walk her two beloved Belgian griffon dogs.

In Gambais, where Landru rented his second house from December 1915 until his arrest, there was one constable in his early seventies, stationed in the village, and a single mounted gendarme in the market town of Houdan, four miles (6.4 km) away.

[22] His eldest son Maurice, born in 1894, was mobilized in the summer of 1915 and arrested soon afterwards for various frauds and thefts, including the receipt and sale of valuables from Landru that had belonged to his first known victim, Jeanne Cuchet.

[25] Lastly, Landru benefited from the indifference of police officers and village officials to the fate of the women, at a time when hundreds of thousands of young men were losing their lives at the front.

On 11 January 1919, Lacoste took her dossier to her local police station in Paris, accompanied by a fellow maid called Laure Bonhoure who had seen Landru when he had visited the house where they worked.

Lacoste contacted Pellat and after conferring about their separate investigations, they filed two missing person complaints with the prosecutor's office in the department of Seine-et-Oise, where Gambais was located.

Belin retrieved the business card that Landru, alias "Lucien Guillet", had given to a shop assistant and visited the address indicated: 76 Rue de Rochechouart, near the Gare du Nord.

[30] The investigating magistrate Gabriel Bonin was initially confident that he could wrap up the case in a matter of days, following the discovery on 29 April 1919 of some tiny fragments of charred human bone debris beneath a pile of leaves in Landru's back garden at Gambais.

Landru had kept the stolen items he had not sold at a garage in Clichy and various storage depots around Paris, along with files on dozens of women he had contacted during the war via lonely hearts advertisements and matrimonial agencies.

[24] In January 1917, following his release from a military prison, Maurice assisted his father in creating a cover story to explain the disappearance of the sixth missing woman, Anna Collomb.

Gilbert allowed photographers to take pictures during each session, a decision which helped to stoke the sensational atmosphere surrounding the long-awaited trial of the "Bluebeard of Gambais".

Celebrities who came to watch Landru included the reigning queen of French musical theatre, Mistinguett, the actors Maurice Chevalier and Sacha Guitry, the writer Rudyard Kipling (in Paris to receive an honorary degree) and the novelist Colette (who covered the first session for the newspaper Le Matin).

Landru's 43-year-old defence attorney Vincent de Moro Giafferri, widely regarded as the most famous trial lawyer in France, privately despised his client and thought he was insane.

[40] However, Moro was also a passionate opponent of the death penalty and did not believe that the prosecution could remotely prove that Landru had certainly killed the 10 women and one young man on the murder charge sheet.

Adding to the impression of his guilt, Landru argued ludicrously that he had pursued the women via lonely hearts advertisements as a means to gain access to their furniture, which he had wanted to sell.

[41] The chief prosecuting attorney Robert Godefroy, a plodding government barrister, struggled from the start of the trial to make any headway with Landru or prevent Moro from undermining the credibility of the police and forensic witnesses.

Yet while Gilbert scored some palpable hits against Landru – in particular, regarding the records in his notebook – the consensus among reporters covering the trial was that the outcome would depend on the closing speeches by Godefroy and Moro.

Landru's notorious oven, in which he allegedly burnt the remains of his victims, was sold at auction in 1923 to a businessman who wanted to put it on display in the Italian city of Turin, beyond French jurisdiction.

In 1947, Charlie Chaplin played the title role in Monsieur Verdoux, a black comedy about a bank clerk who loses his job and murders 14 affluent women to support his family.