A teenage girl who wrote a detailed plan to kill a wealthy elderly woman has been found guilty of murder.

Kemi Adeyoola, 18, stabbed 85-year-old Anne Mendel 14 times at her Golders Green home, in north-west London, during a burglary on March 14, 2005.

Mrs Mendel was discovered by her husband Leonard, 81, lying under a pile of coats in the hallway of their home after returning from an hour-long trip to buy tickets to Israel.

After the verdict, the killer's millionaire father Bola Adeyoola, said: "What she did was evil. She is no longer my daughter. I don't even like her."

Adeyoola, from Camden, in north London, wrote a manual while in custody for shoplifting about her plans to murder an elderly woman.

The blueprint for murder, found at Bullwood Hall Young Offender Institution, detailed how she would lose weight, get a two-bedroom flat, buy bogus GCSEs and A-Level certificates over the internet, get a job and make £3 million.

It also listed how she would get guns and knives and attack a defenceless elderly victim, dismember the body and sell the house.

When asked by police about the 18 pages of handwritten notes - which included recommendations on getting hold of drugs to cause memory loss, to paralyse, knock unconscious and make people tell the truth Adeyoola said they were a draft for a crime thriller.

"With your butcher's knife, remove her head," she wrote. "Wrap it in film to contain bleeding, detach each limb one by one. When you have completed the task, put head and body pieces in black bag." She then plotted to dump the body in bins the day before being collected.

It's expected that she will be sentenced at the Old Bailey tomorrow.

DCI Steve Morris said: "This was a premeditated murder which shows an unusual level of violence in a girl so young.

"Not only did Adeyoola plan and carry out the murder of a defenceless old lady but went to extraordinary lengths to try to conceal her crime with the full compliance of a 16-year-old girl.

"Anne Mendel was well known among the Jewish community in Golders Green where she had many friends. My sympathy goes out to her family at this time."

Mr Mendel said in a statement: "Mrs Mendel was a person whose whole life was taken up with kindness and giving up of herself for others. The unjust end she met having so much taken away in such an undeserving manner left us in total shock.

"We are anxious to express our gratitude to all those concerned with attempting to bring about justice. Although nothing can bring Mrs Mendel back to us we sincerely hope that no-one else will have to endure such a terrible experience."

Adeyoola was charged two months after the attack after her DNA was found on Mrs Mendel's hand.

Explaining how her DNA was found on Mrs Mendel, Adeyoola, who was 17 at the time of the murder, said she had helped the old woman, a former neighbour, cross the road the day before she was killed.

Adeyoola even asked her lawyers to place an advertisement in a local newspaper in December featuring a photograph of herself appealing for anyone who may have seen her on a bus on the morning of the murder.

A 16-year-old girl, who cannot be named, was found guilty of one count of conspiring to pervert the course of justice. Once charged with murder Adeyoola concocted a devious alibi with the 16-year-old to explain why she could not have carried out the killing.