Haigh battered to death or shot his victims and disposed of their bodies using sulphuric acid before forging their signatures so he could sell their possessions and collect large sums of money.

John Haigh was born in Stamford, Lincolnshire,[1] and raised in the village of Outwood, West Riding of Yorkshire.

His parents were engineer John Robert Haigh and his wife Emily (née Hudson), members of the Plymouth Brethren, a conservative Protestant sect.

Thereafter he pretended to be a solicitor named William Cato Adamson with offices in Chancery Lane, London; Guildford, Surrey; and Hastings, Sussex.

Regretting that he had left victims alive to accuse him, he became intrigued by French murderer Georges-Alexandre Sarret, who had disposed of bodies using sulphuric acid.

Haigh later admitted he had lured McSwan into a basement on Gloucester Road, hit him over the head with a lead pipe, and then put his body in a 40-imperial-gallon (180 L; 48 US gal) drum with concentrated sulphuric acid.

[6] Haigh then stole McSwan's pension cheques and sold his parents' properties, for around £8,000, and moved into the Onslow Court Hotel in Kensington.

To solve his financial troubles, he found another couple to kill and rob: Archibald Henderson and his wife Rose nee Burlin.

After feigning interest in a house that they were selling, he was invited to the Hendersons' flat by Rose to play the piano for their housewarming party.

After disposing of the Hendersons' bodies in oil drums filled with acid, he forged a letter with their signatures and sold all of their possessions for £8,000, except for their car and dog, which he kept.

He invited her down to the Leopold Road workshop on 18 February 1949 and, once inside, he shot her in the back of the neck with the .38 calibre Webley revolver that he had stolen from Archibald Henderson,[13] stripped her of her valuables, including a Persian lamb coat, and put her into the acid bath.

Police found Haigh's attaché case containing a dry cleaner's receipt for Olive Durand-Deacon's coat, and also papers referring to the Hendersons and McSwans.

[14] Haigh asked Detective Inspector Albert Webb during questioning, "Tell me, frankly, what are the chances of anybody being released from Broadmoor?

Haigh then confessed that he had killed Durand-Deacon, the McSwans, and the Hendersons—as well as three other people: a young man called Max, a girl from Eastbourne, and a woman from Hammersmith.

Sir David Maxwell Fyfe KC, defending, called many witnesses to attest to Haigh's mental state, including Henry Yellowlees, who claimed Haigh had a paranoid constitution, adding: "The absolute callous, cheerful, bland and almost friendly indifference of the accused to the crimes which he freely admits having committed is unique in my experience.

The editor of the Daily Mirror, Silvester Bolam, was sentenced to a three-month prison term for contempt of court for describing Haigh as a "murderer" while the trial was still underway.