Elizabeth and Katie Edwards were found dead in their UK home last April
A 15-year-old girl has been found guilty of murdering a woman and her daughter while they slept.
The bodies of 49-year-old Elizabeth Edwards and 13-year-old Katie Edwards were found at their home in Lincolnshire last April.
The convicted teenager's boyfriend, also 15, admitted murder last week but neither can be named for legal reasons.
The pair, who were 14 at the time, are one of the youngest couples ever to be charged with murder.
After the killings, the two teenage sweethearts shared a bath, drank alcohol and had sex, before watching "Twilight" movies.
They had carried out the murders following "rational, logical and cold" planning over several days.
The boy killed Elizabeth Edwards first, stabbing her in the throat while she was sleeping and then smothering her.
In an interview with police, the girl said her boyfriend had slowly opened the bedroom door before attacking Ms Edwards.
"He walked into the room and he kind of climbed onto the bed," she told officers.
"He was on top of her. He had a pillow over her face.
"Then after about 10 minutes of him putting his weight on her, she was dead."
The girl said she did not witness Katie's murder in the next room but did hear her mumble something as she was killed by the boy.
The plan was mostly carried out "to the letter", and included stabbing each victim through the voice-box so they could not scream for help.
The girl told detectives that she had "felt like murdering for quite a while" and had intended to take her own life after the killings.
The teenager left a note saying "f*** you world", and asking for her ashes to be scattered at a special place.
In her police interview she said: "A gun would have been easier but we don't have any really in this country... the knife was a better solution."
When asked by officers how her boyfriend seemed afterwards, she said; "He seemed fine. I don't know how he's feeling now but at that moment in time he seemed fine."
When asked how she had felt, the girl said: "I was OK with it. Just the fact that it happened so quickly gave me peace of mind."
The bodies were discovered by police who broke into the house about 36 hours after the murders.
Eight sharp force injuries were found by a pathologist on Elizabeth Edwards' body, of which five were on her hands, suggesting "she may have been trying to fend off her killer".
Her daughter was found with two stab wounds to her neck and a pillow over her face.
A post-mortem examination concluded she died from bleeding and "smothering".
Officers found the murder weapon, a 20cm kitchen knife, discarded on a chest of drawers in the 13-year-old's bedroom.
In court, the prosecution asserted that the girl had "shown no hint of remorse".
A jury rejected the girl's argument that she was suffering from "an abnormality of mental function" at the time of the killings and convicted her of murder.
A consultant forensic psychiatrist, Dr Philip Joseph, asserted that the couple's "intense and toxic relationship" was the catalyst for the killings.
Reverend Mike Chesher, from St Paul's Church in Spalding, knew the victims well and said they were hugely missed.
Ms Edwards helped him run a drama club and the church choir, which Katie was part of.
"The horror of it, the loss of it is going to stay with this congregation for a long, long time", he told Sky News.
"They were part of us and loved very much.
"It seems impossible to understand, impossible because it comes completely out the blue, completely out of the blue.
"For us it must make it harder because we knew them so well. We feel bewilderment and shock."
Kira Nicholls, headteacher of St Paul's Primary school where Elizabeth was a dinner lady, described her as "a warm and loving person who would help anyone with anything, with a big heart and a distinctive laugh" and her daughter Katie as "a kind and thoughtful pupil".
Speaking outside Nottingham Crown Court, DCI Martin Holvey from the East Midlands major crime unit said:
"These two were 14 years of age when they planned (and) committed these callous, senseless and unprovoked attacks on Elizabeth and Katie."
The pair will be sentenced on 10 November.