A young man who killed his mother has been jailed for life.
Emmanuel Kalejaiye, 22, stabbed his mother, Tolu Kalejaiye, more than 40 times at their home in Wickford, Essex, in September 2013.
He then dressed up in a women's tracksuit to try and fool neighours into thinking she was still alive, the court heard.
A jury found the Essex University student not guilty of murder, but guilty of manslaughter by reason of diminished responsibility, due to mental health issues after a trial in April last year.
He has since been in a secure hospital for psychiatric assessment to decide whether his mental condition rendered him a danger to the public.
The case returned to court on Friday, and he was sentenced to life in prison with a minimum of 15 years and three months.
Judge Christopher Ball QC said: "This was an horrific killing. You drew up plans to kill her, over weeks, if not months, and to dispose of the body."
The judge added that mental illness played a part in the killing and said Kalejaiye would receive treatment in jail.
During the trial at Chelmsford Crown Court, the jury heard Kalejaiye had written out a detailed plan including notes on how to walk in high heels and had receipts for pink Primark women's clothing.
Police found a bloodied pink hoodie and pink trousers, which Kalejaiye had bought from Primark a month earlier, as well as scraps of paper detailing an alleged murder plot.
It was said he laid cardboard and plastic down on the floors and wore the pink outfit to move his mother's car to deceive neighbours into thinking that she had left for work.
The jury heard how Emmanuel, who was born in Nigeria but moved to England as a little boy, stabbed his mother to death on the morning of September 26 2013.
Receipts found at the house showed the murder weapon came from a knife block bought by Emmanuel at Lidl just a month before the brutal stabbing.
Mrs Kalejaiye, who worked as an accountant for Camden Council, suffered more than 40 stab wounds to her head, face, neck, upper limbs and hands during the frenzied knife attack.
She called boyfriend, Leo Shogunle, on her phone during the attack at around 7.30am - although he only received the message when he awoke later that morning.
The jury was played a disturbing three-minute voicemail in which the mother-of-two can be heard screaming "don't stab me, don't stab me - you're a demon", before the message fell chillingly silent.
Mr Shogunle raced to the home shortly after 10am on the morning of the attack after hearing the message and let himself in using a spare key.
He was confronted by the bloodied body of his lover lying on the kitchen floor and Emmanuel, who said his mother had been attacked before fleeing the scene.
Emmanuel was later caught on CCTV at around 10.30am calmly buying a can of coke and a pack of Maryland cookies at a local post office before handing himself in to police.
During police interview, he signed a confession stating:
"I admit killing my mother this morning by stabbing her. I did this because she subjected me to a lifetime of physical and mental abuse.
She used the Bible to rationalise what she did to me. I believe she manipulated and brainwashed me.
I have been very depressed for a long time. I have tried to overcome it but I couldn't take it anymore."
Kalejaiye later changed his story saying a gang of masked men burst into his home, forced him to stab his mum then threatened him with further violence if he told police.
He told the court a gang of five white, balaclava-clad men targeted him in a suspected racist attack.
The university student went onto claim the mystery men had forced him to dress up in the pink clothing and pink flip flops to move his mother's Mercedes car - a move the prosecution claimed had been an attempt fool neighbours into thinking his mother had driven to work.
He also ran a separate, partial, defence of diminished responsibility on the grounds that he had been diagnosed as a paranoid schizophrenic and had a depressive disorder.
During the trial the prosecution alleged that Emmanuel disliked his mother, who was described as strict, stubborn and with an explosive temper, and that he 'meticulously' planned to kill her.
Evidence from an expert psychiatrist stated Kalejaiye had been suffering from severe depression and paranoid schizophrenia at the time of the attack.
The court heard how fellow students at Essex University, where Emmanuel had studied biochemistry, found him 'weird and paranoid'.
Before sentencing, Kalejaiye's counsel, John Benson QC told the judge: "It was horrific incident, harrowing for anybody listening to the 999 call.
"She died in terrible circumstances and he will have to come to terms with taking the life of his mother."