A son launched a knife attack on his mother and her partner, the millionaire businessman Sir Richard Sutton, on the anniversary of his father’s death, seething with resentment over how he felt the couple had treated him, a murder trial has heard. Thomas Schreiber, 35, who killed Sutton, 83, a hotelier and landowner, and inflicted life-changing injuries on Anne Schreiber, 66, believed the pair favoured his two sisters, which left him feeling like an outcast, the jury was told. The court also heard that there had been two violent incidents before the knife attack, including one that erupted during a row over a chandelier and ended with Sutton hitting Schreiber so hard with his walking stick that it broke. Tensions were also rising before the “explosion of violence” in April at the family’s Dorset mansion because Schreiber, his mother and her partner were locked down together at the height of the Covid pandemic, it is alleged. Adam Feest QC, prosecuting, said there was no disputing that Schreiber had killed Sutton and seriously injured his mother, but that the defendant’s state of mind would be a key element for the jury to consider. Schreiber denies murder and attempted murder. Jurors heard a string of messages recorded in the weeks and months before the attack in which Schreiber expressed his hatred for his victims and talked of revenge. He told one friend: “I have a plan which I’m working on … Revenge is at its heart.” He confided to another: “I would like to get a gun and shoot a bullet in my mum’s face and Richard’s.” The month before the attack he wrote: “My mind is consumed with hatred of the very worst kind towards my family … I contemplate murdering them … day and night … I want them to suffer.” Schreiber visited his father’s grave on the day of the attack. His mother told police she was in the kitchen when she turned to see him holding a 15cm long knife. His eyes were “almost frightening to look at because they looked terribly, terribly determined”, she said. He appeared wild and “very, very unusual, very, very out of control”. She suffered as many as 15 wounds and needed about 27 litres of blood products – the human body holds between four and six litres. Among her injuries was a vertical cut to the right side of her face from her eyebrow to her chin, but the most significant was a partial transection of the spinal cord, which had caused “serious, ongoing physical consequences”, the jury was told. Feest said Sutton had been estranged from his wife, Lady Fiamma Sutton, for almost 20 years while Anne Schreiber and her husband, David Schreiber, separated in about 2002-03. This, the prosecutor said, was caused at least in part by David Schreiber’s alcoholism, which put a strain on their marriage emotionally and financially. In the summer of 2003 Anne Schreiber and her three children were invited by Sutton to move to his mansion, Moorhill. David Schreiber moved into a cottage on the estate where he lived until his death in 2013. Feest said the defendant took his father’s side and felt his mother was “toxic” and she and his sisters “gold-diggers”. In Christmas 2018 after a trip to Wincanton races, the family argued over the defendant not offering to drive, the court was told. Sutton intervened, and may have swung a fist at Schreiber, who hit the older man in the face. In November 2020 Ms Schreiber suggested to one of her daughters, Louisa, that she might have one of their grandmother’s chandeliers. Schreiber lost his temper and became abusive to his sister. Sutton stepped in and hit Schreiber across the back with his walking stick so hard it snapped. After the attack on his mother and her partner in April, Schreiber fled and telephoned relatives and friends. He told one friend: “I’ve killed my mum and I’ve killed Richard and I’m here lying in blood and I’m about to kill myself.” In a reference to the chandelier episode, he told another: “I don’t appreciate being knocked around by Richard.” The trial continues.