Catastrophic errors left a prolific and proven sex offender free before he murdered two women in London, it can be revealed.On Friday an Old Bailey jury found Simon Levy, 40, guilty of murdering Carmenza Valencia-Trujillo in March 2025 and Sheryl Wilkins five months later.Levy was on bail as a suspect for the first murder when he committed the second, with police saying they lacked the evidence to charge him.Months before his first killing, police had arrested Levy for sexual assaults of women on trains, but made errors that delayed his charging. While on bail he committed more attacks, taking the number to 10 across London. He was charged for most, yet remained free and committed his second murder.Prosecutors also admit bungling efforts to have Levy remanded to prison, failing to give three court hearings key information that showed the full extent of Levy’s potential danger to women.But even before the train attacks, police and prosecutors knew Levy was a proven danger.He was first jailed for sexual violence in 2021 and while in jail he sexually assaulted a female prison officer.After his release he committed sexual assaults on trains across London from 2023 to 2025. He was also the prime suspect in a rape case.Then in January, March and August 2025, Levy, from Tottenham, north London, savagely attacked three women who provided sexual services, and left them for dead.Levy was convicted of the murder of Valencia-Trujillo, 53, in a partially disused tower block in south-east London on 17 March 2025.The scene of the killing was close to where Levy had lived on release from prison after his first convictions for sexual offences.The jury also found him guilty of the murder of Wilkins, 39, in a car park in Tottenham on 24 August 2025.Sheryl Wilkins (left) and Carmenza Valencia-Trujillo. Composite: Metropolitan police/Family handout/PAAnd he was convicted of raping and attacking a third woman, 35, in January 2025, who survived. She was attacked in the same Tottenham car park, eight minutes’ walk from the home Levy shared with his mother and sister.The Crown Prosecution Service (CPS), the Metropolitan police and British Transport Police (BTP) have all admitted errors.Kevin Southworth, a deputy assistant commissioner at the Met, which investigated the killings, described Levy as “a prolific, predatory monster”.He said Wilkins, the second murder victim, would probably have been alive if not for the errors which he blamed on “collective system failures”.The litany of failings can only be reported now that Levy’s murder trial has ended, leading to the lifting of reporting restrictions on that and a trial earlier this year.A jury in February convicted him of 10 sexual assaults on trains, including one on a daughter travelling with her mother, as well as the attack on a female prison officer while he was in jail.Police first arrested Levy for a number of attacks on trains in November 2024, with CCTV tying him to the scene of the assaults. Six more occurred in the first five months of 2025.The errors and questionable decisions included: