A 15-year-old girl accused of working with her boyfriend to murder a mother and daughter was the driving force in the killings, a court has heard.
The girl, who cannot be named, is accused of murdering Elizabeth Edwards, 49, and Katie Edwards, 13.
The pair were stabbed in the neck at their home in Spalding, Lincolnshire, in April.
The girl has admitted manslaughter on the grounds of diminished responsibility but denies murder.
A 15-year old boy has admitted murdering both women. The accused were both 14 at the time of the killings.
The girl did not physically take part in their killings but the prosecution alleges she “is as guilty of murder” as the boy.
In his closing speech to jurors at Nottingham Crown Court, prosecutor Peter Joyce QC said: “This case, I would suggest, is outside any of your experiences and worst nightmares, but, as the old saying goes, truth is stranger than fiction.
“Which of you could imagine that a 14-year-old girl and a 14-year-old boy could plan over and over and over again to kill [these two women]?
“You do not need to imagine it, it’s true and it’s completely unchallenged by this girl.”
He told jurors: “…You know what they planned, you know how they planned it and you know in awful detail how they carried it out.
“But you also know who in fact was the driver between these two.”
“If she had said no then it would never ever have happened,” he said.
Closing for the defence, barrister Andrew Stubbs QC reminded the jury of the evidence of Dr Chakrabati who diagnosed the girl as having an adjustment disorder at the time of the killings.
He also urged the jury to consider the girl’s mental state before the killings, pointing to an entry in her diary which read “Help me. Death is the only way. Madness is in me.”
He told the jury to undertake “a calm analysis of the evidence”, adding that “on the balance of probabilities you can conclude that justice in this case means that however responsible she is for the killings she is in fact not guilty of murder”.
The trial continues.