A sports psychologist who murdered his mum claimed he bludgeoned her to death because she was trolling his estranged wife on Twitter.
Robert Child, 37, admits murdering 64-year-old Janice Child at her home in Woolton on March 5 this year, but denies the killing was for financial gain.
The killer, who confessed to lying to friends and family about having a PhD and working for Manchester United as a scout, transferred £25,000 from Mrs Child's savings to his bank account moments after he left her home, having battered her with a hammer and locked her in the utility room.
When police arrived at his home in Thingwall, Wirral the following morning to inform him of her death, he was out buying a £14,000 Jaguar car.
Today he gave evidence at a Newton Hearing – a form of mini-trial where a judge establishes disputed facts of a case – about his motives.
Child told Liverpool Crown Court he went to see his mum to tell her he planned to kill himself, but they began to argue when he said he was "struggling".
He claimed she used "derogatory racist terminology" about his estranged wife, Sangee Perera, a Sri Lankan national.
Child said: "She disliked her for no other reason than the colour of her skin."
Child told the court he separated from Ms Perera in 2015 but they remained married, despite him planning a wedding – which he later cancelled – to his new partner, Kelly Williams.
He suggested his mum revealed she had sent a fax to the Home Office to withdraw a visa application for Ms Perera.
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Child added: "She indicated that she had been following her on social media and had been attacking her online."
He claimed Mrs Child showed him a Twitter log-in page with a number of different email addresses and told him every time Ms Perera blocked her, she opened a different account.
Child said: "I had been in regular contact with Sangee since and I had known she had been attacked and trolled online by an unknown person or persons.
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"I was aware of the effect it had had on her mental health in the previous 12 to 18 months and the idea that had come from my mother, five years after that relationship had come to an end, was a shock."
The court heard no evidence of any Twitter accounts being found on Mrs Child's laptop.
Child said he had followed his mum into the utility room while arguing with her and attacked her with a hammer, which was lying on the washing machine.
He said: "I had made the decision that my life was going to end prior to going there that day and I think I had the conscious thought that if she was still around she would continue to attack Kelly and Sangee with even more venom."
Child, who told the court he had more than £17,000 in crypto-currency investments, accepted he had struck his mother 31 times.
He said: "I remember the first strike. I do not remember the others. It was a frenzied attack, I do not recall."
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The defendant, who worked for the University of Liverpool on a consultancy contract, claimed he planned to buy the Jaguar with funds from a joint account he and his mum had, but she had offered to give him the money from her own account while the withdrawal cleared.
Child said he intended to drive the car to Italy and then take his own life there.