Peter Thomas Anthony Manuel was born in Manhattan on March 13, 1927, to Scottish parents who returned to Lanarkshire when he was five. He was in approved schools from eleven and had convictions for housebreaking, indecent assault and rape by his twenties, having served eight years for one of them. He was articulate, vain and a persistent liar, and he had a habit of talking to police about crimes he was supposedly helping them with.
He killed Anne Kneilands, a seventeen-year-old, on a golf course at East Kilbride in January 1956. In September 1956 he broke into a bungalow in Burnside and shot Marion Watt, her sister Margaret Brown and her sixteen-year-old daughter Vivienne in their beds. Marion's husband William Watt, who was away fishing, was arrested for it and held for sixty-seven days in Barlinnie before being released. Manuel afterwards met Watt in a Glasgow hotel and told him things about the inside of his own house that only the killer could know. The Scottish press called him the Beast of Birkenshaw, after the village he lived in.
In December 1957 he killed Isabelle Cooke, a seventeen-year-old walking to a dance in Mount Vernon, and buried her in a field. Around the same time he shot Sydney Dunn, a taxi driver, near Newcastle. On New Year's Day 1958 he broke into a house in Uddingston and shot Peter Smart, his wife Doris and their ten-year-old son Michael as they slept, then stayed in the house for several days, eating their food and feeding their cat. Anna Knielands, seventeen, killed in January 1956, was the first.
He was caught by money. The Smarts had drawn new banknotes for a holiday, in sequence, and Manuel spent them in Glasgow bars. He was arrested on January 13, 1958, and after his father was charged over a stolen item found at the house he made a full written confession to a series of murders, saying he wanted his parents left alone.
He was tried at the High Court in Glasgow in May 1958. Partway through he dismissed his counsel and conducted his own defence, cross-examining William Watt, the man his own crime had put in prison, and doing it well enough that the judge remarked on it. He was convicted of seven murders on May 29 and hanged at Barlinnie on July 11, 1958, one of the last men executed in Scotland.