A scorned lover has been jailed in England for at least 22 years for a ferocious knife attack on her own sister in a bid to win back the affections of her brother-in-law.
Carer Sabah Khan, 27, had been having sex with Hefeez Rehman, husband of her older sister Saima Khan, 34, with whom she was living in Luton, Bedfordshire.
But when Mr Rehman's attentions cooled and he returned to the mother of his four children, Khan became bitterly jealous and plotted for weeks to get her out of the way.
She searched the internet for how to get away with murder and paid a "black magic priest" in Pakistan £5,000 to do the deed by "remote control", the Old Bailey heard.
The carer bought a large kitchen knife from Tesco and, on May 23 last year, lured her sister home from a family funeral, saying one of her children was crying.
She donned gloves and black clothes and lay in wait.
Then as Saima Khan returned, she switched off the lights and carried out a "vicious and sustained" attack in the hallway, with the children upstairs.
Over eight minutes, she inflicted 68 sites of injury to the head and body, slicing through her hand and neck, the court heard.
It was a scene of "absolute carnage" and Khan carried on stabbing her sister, even after she was dead, Judge Christopher Moss QC said.
Khan went on to stage the scene of a burglary before calling her father and 999, claiming she was in the shower when her sister was attacked by an intruder.
The defendant stuffed her bloodied clothes, gloves and murder weapon into a bin bag which was later found in a bedroom at the Overstone Road house.
She went on to claim to police she had overheard a phone call between her sister and a lover who threatened to harm her.
Khan pleaded guilty to murder and was jailed for life by Judge Christopher Moss QC.
Prosecutor Jane Bickerstaff QC told how WhatsApp messages revealed Khan's bitterness as Mr Rehman's interest in her waned.
She referred to her sister as "that bitch", and told Mr Rehman: "If I could I would take my heart out and show you what you are for me.
"Nothing in the world can change my feelings for you. Not even you ... Day by day my love for you gets stronger."
Ms Bickerstaff said: "From February, all was not well with Hefeez Rehman and his affection appears to have been transferred back to his wife."
Around this time Khan searched the internet for "poisonous snakes" "how to hire a killer" and "16 steps to kill someone and not get caught".
She was also in frequent communication with a "fixer" in Pakistan and handed him over £5,000 to have her sister "finished off" and "done in".
She told the fixer: "Sorry to bother you again and again. My friend is really upset now Hefeez does not even look at her ....he says he realises his mistake ... You finish off Saima as quick as possible so Sabah can get her Hefeez back."
The prosecutor said there was an added time pressure as her sister and her family were due to move out later that month.
Mr Rehman was not in court but said in a statement: "I feel complete shame about having an affair with Sabah.
"I never imagined anything like this would ever happen. Sabah's actions have left our four children without a mum.
"I have four beautiful children but I have lost my world and I cry every day. Saima was there for all four children. She did everything
"There is not a day goes by when I don't regret my affair with Sabah."
Paying tribute, the cab driver said: "My wife Saima was a lovely, caring, kind, wife and mother. She was quiet but loved laughing and joking within the family."
Mitigating, Jo Sidhu QC said: "This defendant, for the rest of her natural life, will live with what she has done."
He said it was a unique case and "against nature" for one sister to kill another.
Mr Rehman was 10 years Khan's senior and had taken advantage of the opportunity to sleep with both siblings and gain "exclusive rights" over his sister-in-law, the lawyer said.
Mr Sidhu quoted from Mr Rehman's account in which he described being "forced" to have sex with Khan, who threatened to harm herself if he did not.
He said his wife knew she "really liked" him but he never admitted he was having sex with her.
The husband also admitted that during his marriage he had sex with another woman in his cab, on a visit to Pakistan, and paid prostitutes.
The court heard Khan's detailed web searches included investigations into drug overdoses, poisonous snakes, rat poison and even polonium.
Detective Chief Inspector Adam Gallop, of Bedfordshire Police, said: "This was a brutal act of jealousy. It was not a case of honour killing, nor was this the burglary that Sabah Khan tried so hard to create.
"Sabah wanted her sister's life. She wanted her children and her husband. Hearing the news that they were planning to leave the family home together was the final straw and she took her sister's life in a bitter envy.
"Everyone working on this case has struggled to comprehend the extent of the force used and injuries sustained at the hands of this young woman's own sister.
"These actions can only be fuelled by a deep level of hatred; hatred that had been concealed from the rest of the family.
"I am pleased that the sentence reflects the pre-meditated actions that cut short a young woman's life and deprived four young children of growing up with their mother."