[3][10] Mackay was supposedly unable to come to terms with the loss of his father, telling people Harold was still alive and keeping a photograph of him on his person.

"[11][3] He was removed from his family home on eighteen occasions between the ages of 12 and 22 and put into various specialist schools, institutions and prisons.

[12] As he entered adulthood, Mackay developed a fascination with Nazism, calling himself "Franklin Bollvolt the First" and filling his flat with Nazi memorabilia.

[3] Known for being home to the wealthiest London residents and full of luxury shops and high-end restaurants, the areas suddenly saw a massive, unexplained rise in muggings, robberies and handbag snatchings.

[3] Thirteen months later, on 10 March 1975, elderly Adele Price was also killed in her Chelsea home by Mackay who had entered her property asking for a glass of water.

[3][2] Her granddaughter was coming home at the time and, without knowing, passed the killer as he left the premises after attacking the woman.

[2] An investigating police officer remembered an incident that had occurred some months earlier involving the young Mackay, who had befriended the priest only to break into his home and steal a cheque for £30.

[3] Jewellery and silver fountain pens were found in Mackay's home which had come from robberies he had committed in the Chelsea and Belgravia areas.

[2] The Metropolitan Police began to investigate Mackay and he was found to have committed many other of the unsolved murders and crimes in the London area.

Detectives checked his descriptions of some of the killings and found they indeed matched details of unsolved murders that had occurred in and around London.

[13] The sixth murder was of Frank Goodman on 13 June 1974, who had been beaten to death with a metal bar over a pack of cigarettes.

[13] The seventh: Mackay allegedly confessed to the murder of 92-year-old Sarah Rodmell in her flat in Hackney on 23 December 1974, saying that he had nailed the back door shut and put her stockings in her mouth, and that "killing her was as easy as washing my socks".

[13] The eighth murder was of 48-year old café owner Ivy Davies in Southend in February 1975; the killer had beaten her with a tent peg.

[13][17] Mackay confessed that he knew of the shop and considered robbing her, but when he was driven to view her café and nearby home, he could not recognise them.

[18] Investigators concluded that Mackay had been the perpetrator of the mugging and theft spree in Chelsea and Kensington, crimes which were previously unsolved.

[3] Mackay denied his confessions to all but four of the murders (Griffiths, Price, Crean and the homeless man he said he had thrown from a bridge in January 1974).

[16] At his trial in November 1975, Mackay was convicted of the manslaughter of Adele Price, Isabella Griffith and Father Anthony Crean after pleading guilty on the grounds of diminished responsibility.

[1] In 2019 Dartford MP Gareth Johnson voiced concern at the potential release of Mackay, raising the issue in Parliament and writing to the Secretary of State for Justice.