A GP has admitted trying to kill his mother’s long-term partner by disguising himself as a community nurse and poisoning him with a flesh-eating toxin disguised as a Covid jab. Thomas Kwan, 53, injected his victim with the life-threatening chemical after what prosecutors described as “one of the most elaborate criminal plots in recent memory.” The Hong Kong-born doctor had wanted to kill Patrick O’Hara, 72, so he could inherit his mother’s estate when she died, Newcastle crown court was told. Kwan initially denied attempted murder but changed his plea on Monday after the prosecution opened the case against him. He had been a respected and experienced GP in Sunderland when he devised an elaborate plot to murder O’Hara at his mother’s home on 22 January. Over several months, Kwan had plotted how to get access to his victim using shell companies, counterfeit documents and elaborate disguises. The doctor had an “encyclopaedic knowledge” of poisons and had studied how to get away with murder, the prosecutor, Peter Makepeace KC, told jurors last week. Kwan’s plan fell into place when he wrote to O’Hara last November claiming that the then 71-year-old was a priority for a home-visit Covid booster jab because of his age. Makepeace said: “As, I suspect, would any of us, Mr O’Hara fell for it hook, line and sinker; he had not the slightest suspicion that this was anything other than a genuine NHS community care initiative which he warmly welcomed and was grateful for.” Kwan went to his mother’s house in a long coat, flat cap, surgical gloves and wearing a medical mask and tinted glasses. He carried out a 45-minute examination of O’Hara, and even checked his unsuspecting mother’s blood pressure when she asked. Kwan, in what the court heard was broken English with an Asian accent, told O’Hara he needed a Covid booster, even though he had had one only three months earlier. O’Hara, who had been Kwan’s mother’s partner for more than 20 years, shouted in pain when it was administered and Kwan hurriedly packed his equipment and left, reassuring his victim that a reaction was not uncommon. The pain continued and O’Hara began to suspect something had gone badly wrong. The next day his arm had blistered and was seriously discoloured and hospital medics were baffled. He had developed the flesh-eating disease necrotising fasciitis and needed to have part of his arm cut away to stop it spreading. He spent several weeks in intensive care. The fake nurse’s movements were traced using CCTV and police were able to identify Kwan as a suspect. The poisoning led to an emergency services operation when police found lethal chemicals stored in the detached garage at Kwan’s home in Ingleby Barwick, Teesside. Searches of his home in the executive estate where he lived revealed an array of chemicals such as arsenic and liquid mercury, as well as castor beans, which can be used to make the chemical weapon ricin. Kwan never revealed what type of poison he used to try kill O’Hara but police initially thought he had used ricin. A Ministry of Defence chemical expert thought a more likely candidate was iodomethane, predominantly used as fumigant pesticide. Jurors were told that this was believed to be the first recorded medical case of any human being injected with iodomethane. The GP had drawn up two other plots for if he did not go ahead with the Covid booster jab ruse. One involved a document, found in Kwan’s house, purporting to be from the “Northern England Men Sporting Association”, addressed to “Patrick” and offering him free drinks and ready meals through the post in recognition of his contributions to the north-east throughout his working life. Kwan had developed the obsession after his mother, Jenny Leung, named O’Hara in her will to the effect that he could stay in her house in Newcastle should she die before him. That decision strained the relationship with her son to the point that police were called when Kwan burst into her home uninvited in November 2022. Kwan was “money-obsessed”, jurors heard, even installing spyware on his mother’s laptop so he could secretly monitor her finances. The GP had admitted administering a noxious substance but claimed that he only meant to cause mild pain. DCI Jason Henry of Northumbria Police described Kwan’s actions as “utterly despicable”. He said O’Hara had “been through a horrendous ordeal, his life has changed for ever”, and added: “He has shown incredible strength throughout the investigation and we will continue to support him in any way we can.” The Crown Prosecution Service (CPS) described it as “one of the most elaborate criminal plots in recent memory”. Christopher Atkinson, head of the CPS’s complex casework unit in north-east England, said the impact on the victim had been “catastrophic”. He added: “The chemical injected caused increasingly severe damage, beginning with burns and blisters around the injection site and progressing into a potentially life-threatening flesh-eating disease. “At a time when Kwan could have assisted medical staff by identifying this substance, he instead made no comment to the questions put to him in police interview, allowing the victim’s health to further deteriorate.” The judge, Mrs Justice Lambert, said Kwan would face a “substantial” prison term at his sentencing on 17 October.