Teenagers locked up for at least 20 years for murder of Edinburgh mother and daughter

The teenagers, now 15, went on to share a bath, have sex, and watch four Twilight vampire films after the murders in Spalding, Lincolnshire, last April, Nottingham Crown Court heard.

Sentencing the pair, who cannot be named for legal reasons, to life with 20-year minimum terms, Mr Justice Haddon-Cave said: "This case is, in many respects, without parallel."

The judge said the case had "defining and particularly chilling" features, including the young age of the defendants and that the offence was carefully planned.

As both teenagers remained composed in the dock, flanked by security guards, the judge condemned their conduct after the killings as "grotesque".

He told the teenagers: "This is a case of double murder. One of the victims was a young girl. There is a clear intention to kill both victims - both defendants admitted wanting to murder them.

"There was remarkable premeditation and planning - it was, on any view, substantial, meticulous and repeated.

"The killings were brutal in the form of executions and both victims, particularly Elizabeth Edwards, must have suffered terribly in the last minutes of their lives."

The couple - who the court heard had a Bonnie and Clyde-style relationship - carried out the "cold, calculated and callous" attack which saw the two victims stabbed a total of 10 times.

Both the boy and the girl pleaded guilty to manslaughter but not guilty to murder at a hearing in September, with the male defendant admitting murder before the trial began.

His girlfriend maintained her innocence to murder, claiming to be suffering an abnormality of mental function which impaired her ability to form rational judgments, but was found guilty after a five-day trial.

During his sentencing remarks, the judge said both teenagers were equally responsible for the murders.

"This was an entirely joint offence," he told them. "You were in it together from the beginning, you conceived of the killings together and planned it together.

"Both of you are perfectly intelligent and knew exactly what you were doing - either of you could have backed out at any time but you were selfishly determined to do it together.

"You had then revelled in what you achieved. I see no reason to distinguish between you in any way."

The judge went on: "I have carefully read the victim impact statements in this case. They are a poignant testimony to the devastation and heartbreak that this horrific event has caused."

Speaking outside court, Karen Thompson, deputy chief crown prosecutor at CPS East Midlands, said: "This is one of the most distressing and disturbing cases that I have ever encountered.

"The male defendant accepted his guilt on the first day of trial. The other defendant maintained her not guilty plea but, after the jury heard all the medical evidence presented they concluded that any difficulties that she may have had did not prevent her forming an intent to kill.

"Our deepest sympathies are now with the extended family and friends of Elizabeth and Katie Edwards as they attempt to come to terms with this horrific crime."

The judge stressed that neither teenager will be freed until they have served their minimum term and the Parole Board approves their release.

"Had you been adults you may have been facing the whole of your lives in prison for this double murder," Mr Justice Haddon-Cave told them.

The boy slouched in his seat with his arms crossed and stared at his legal team as the court heard how he told police one of his victims fought back for up to three minutes.

The teenager showed no emotion as prosecutor Peter Joyce QC, outlining the boy's account, told the court that Mrs Edwards had struggled and scratched her attacker's face.

Mr Joyce added: "He had picked up the knife and the girl came to him and asked, 'Is it done?', to which he had replied, 'Yes'. She then asked, 'Did she struggle?', to which he had replied, 'Yeah'."

According to the boy's statements to police, he then went into Katie's room, bent down and pushed the knife through her throat before using a pillow to smother her.

Offering mitigation before sentencing, defence QC Simon Myerson, representing the boy, said: "The reason these offences were committed was, as far as anyone can ascertain, the two children became trapped in a fantasy of their own devising.

"It's inconceivable that had they been fully mature, had they not been subject of their own personality disorders, that these offences would have been committed by them."

Andrew Stubbs QC, representing the girl, said his client was "still plainly coming to terms with what she has done".

He added the couple were in a "toxic relationship" and they were "almost playing chicken with each other" as they spurred each other on to commit the killings.

Detective Chief Inspector Martin Holvey said: "This has been a rare and unprecedented case and everybody who has listened to the details as they have emerged throughout the trial will, I am sure, have felt the same sense of shock and disbelief.

"The planning that went into the brutal murders of Elizabeth and Katie as they slept in their beds was cold, ruthless and chilling, as was the lack of remorse shown by the two juveniles afterwards."