Two 15-year-olds have been given life sentences with 20-year minimum terms for the murder of a mother and daughter in Spalding, Lincolnshire in April, 2016.
The boyfriend and girlfriend, who cannot be named for legal reasons, were both 14 when they smothered and stabbed a school dinner lady Elizabeth Edwards and her daughter Katie, 13, while they slept at home in Spalding.
The boy pleaded guilty to the murders ahead of a trial last month.
The girl, who had admitted manslaughter, was also found guilty of murder, after the court was told she was the “driving force” behind the killings, because she held a grudge against the victims.
A suicide note written by the girl after the killings, said: “F*** you world.
“I want to be cremated and I want mine and [the boy]’s ashes to be scattered at our special place.
“We don’t give a f**k anymore.”
While dishing the sentence to them, the judge said it was “a terrible crime which has few parallels in modern criminal history”.
The killers were 14 at the time, apparently making them Britain’s youngest double-murderers.
The judge at Nottingham Crown Court, Mr Justice Haddon-Cave, said the case had “defining and particularly chilling” features, and condemned the killers’ conduct as “grotesque”.
Jurors heard that the killers went on to share a bath, have sex, and watch four Twilight vampire films after the murders in Dawson Avenue, Spalding, on 13 April.