London: Luton, which has a large Pakistan community, has been shaken by a horrific killing - a sister has admitted cutting her elder sister's throat and severing her hand.

Sabah Khan, 27, of Overstone Road in Luton, was due to face trial for the murder of 34-year-old Saima Khan, a care worker and mother of four, on May 23, 2016.

But at a brief hearing at the Old Bailey this week, she admitted the charge.

Hence the reason for the attack has so far not been disclosed.

It is understood that Saima had moved to England from Holland several years ago and lived with her sister, their parents, her children and her husband.

Saima's husband, Hafeez Rehman, a taxi driver, said of his wife: "She was a loving mother to four beautiful children, a devoted wife, a beloved daughter and the most caring of sisters.

"She has been taken from us at the age of 34 and my children have been deprived of their mother.

"This was a junction in our lives where we intended to watch our children grow, to love them and spend quality time as a family and make memories.

"We have been left with a gap in our lives and we can only pray that she is resting in peace. As everyone can appreciate and understand that the circumstances have torn our hearts apart.

"My family and I would like to thank you all for the condolences messages, and support that we have received from family, friends and the local community."

Sabah is believed to have virtually cut her older sister's neck in half and severed her hand in the frenzied knife attack.

The children were asleep upstairs when Sabah carried out the attack in the semi-detached house the family shared in Luton.

Saima was found slumped in a pool of blood in the hallway of her home at about 11.30pm.

Other family members were absent at the time because they were attending the funeral of an elderly aunt.

At first detectives investigated claims that a burglar had got into the property and had carried out the killing. A forensic tent was pitched outside the dwelling as police searched for clues.

Following her plea, Detective Chief Inspector Adam Gallop of Bedfordshire Police, said: "This is any family's worst nightmare - it is beyond comprehension for the family to hear that one daughter has brutally murdered another.

"It has been a horrendous ordeal for them and we are pleased that we have received the guilty plea. We continue to support the family; I'm not sure there can ever really be a closure, but what I do hope is that after sentencing they can hear what happened that night and start to move forward."Sabah appeared in court wearing a black top and black trousers as her barrister Jo Sidhu QC asked that the case be adjourned and that she be sentenced later. Sabah, who is held in custody, is due to be sentenced in due course by Judge Christopher Moss. QC who has no option but to give her life.

The prosecution may give reasons for the killing.

Reasons for the killing emerged today - the oldest in the world - as Sabah was jailed for at least 22 years.

Sabah had been having sex with Hefeez but when her brotherinlaw's attentions cooled and he returned to his wife, his scorned lover became bitterly jealous and plotted for weeks to get Saima 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.

Sabah 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 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 slashes to the head and body, slicing through her hand and neck, the court heard.

It was a scene of "absolute carnage" and Sabah carried on stabbing her sister, even after she was dead, Judge Christopher Moss QC said.

Sabah 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.

She went on to claim to police she had overheard a phone call between her sister and a lover who threatened to harm her.

Prosecutor Jane Bickerstaff QC told how WhatsApp messages revealed Sabah's bitterness as Hefeez's interest in her waned.

She referred to her sister as "that bitch", and told Hefeez: "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."

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 Sabah searched the internet for "poisonous snakes","how to hire a killer" and "16 steps to kill someone and not get caught".

Hefeez 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.