A woman beat her ex-boyfriend to death while he was on the toilet after decades of abuse against him and then hid his body under a tarpaulin for nearly a year, a court heard.Robert Kellett, 62, was found dead in a bathroom, wrapped in a tarpaulin on September 12 last year - 11 months after he was reported missing.His body was discovered in an 'advanced state of decomposition' at the home he had shared with his ex-girlfriend Cheryl Downs, 66, in Terry Road, High Wycombe.Downs is charged with Mr Kellett's murder and is on trial at Aylesbury Crown Court.Today, she admitted to killing Mr Kellett but is expected to argue she did so in self-defence or has diminished responsibility due to her mental state.She has also accepted charges of preventing a lawful and decent burial, and attempted fraud in relation to her conduct after his death.Prosecuting, Caroline Carberry KC said: 'The relationship between the defendant and Robert Kellett was long‑standing, but deeply troubled.'It was characterised by Cheryl Downs' volatile personality, financial pressure she put on him, by lies she told about him and by conflict. Robert Kellett's rotting corpse was found dead in a bathroom, wrapped in a tarpaulin on Terry Road in High Wycombe by a teenage lodger Cheryl Downs had arranged to move in last September Downs, 66, is charged with the 62-year-old's alleged murder and stands trial at Aylesbury Crown Court. She admits killing Mr Kellett but claims it was in self defence'Her killing of Robert Kellett was the culmination of years of controlling and abusive behaviour by her towards him.'And it came at a time when Mr Kellett had moved out of the house they owned, away from the area and was attempting to start a life independent of the defendant.'Mr Kellett died by fatal head trauma - his body found with several fractures to his skull, caused by 'repeated blows' with a heavy implement, over the weekend on October 5-6 2024, the court heard.He had moved out of the house at the time of his alleged murder, but had gone back for the weekend as he was still assisting Downs financially.'Mr Kellett was in the bathroom, most likely on the toilet, when he was initially attacked and then incapacitated and helpless on the floor as the attack continued,' said Ms Carberry.Psychologists identified 'narcissistic and psychopathic' personality traits in Downs, and Mr Kellett 'feared for his safety' during their relationship, jurors were told.After his death, Mr Kellett, who had been working as an engineer in the West Midlands, was reported missing by his boss.The police attended the Terry Road home trying to find Mr Kellett, but Downs refused to let them in, and told the officers that she had not seen him, the court heard.By this time she had moved his car from outside the house, and the police did not investigate further at that time.The body was discovered 11 months later by a teenage lodger who was moving into Downs' house, the court heard.'It seems as if the defendant wanted Robert Kellett's body to be found and she was prepared to use her young lodger for this to happen,' said Ms Carberry.The lodger and her boyfriend went to investigate the 'terrible smell' and made the 'grim discovery' of Mr Kellett's remains in September 2025.Mr Kellett had contacted the police about Downs' behaviour towards him several times from 2010 onwards, with the most recent report coming just five days before he was killed.Downs was arrested multiple times for assaulting Mr Kellett, but on each occasion he did not press charges, the court heard.The prosecution said Downs' 'physical abuse and intimidation' was worse when she was drinking, and that she would 'manipulate' Mr Kellett.They also said that Downs would control Kellett's finances, and paid for wine and cigarettes using his card the day after she had killed him.Downs' neighbours had also reported her to police multiple times, as she was verbally abusive to them and would 'scream like a banshee' at Mr Kellett and 'bang on the walls' during the night, the court heard.Ms Carberry said: 'One couple, who had lived in their home for many years, sold up to get away from her.'As she was leaving, the defendant shouted at her neighbour that she would kill her if she ever returned.'The trial continues.