The mother of a Nottingham stabbing victim said “true justice has not been served” after the killer was sentenced to indefinite detention in a high-security hospital. Emma Webber, the mother of 19-year-old Barnaby Webber who was killed alongside fellow student Grace O’Malley-Kumar in the violent attacks that left three people dead last year, also said the assistant chief constable of Nottinghamshire police had “blood on his hands” over the force’s failure to arrest the killer in the months before the killings. “We as a devastated family have been let down by multiple agency failings and ineffectiveness,” she said, adding that they had been “rushed, hastened and railroaded” into accepting Valdo Calocane’s manslaughter pleas. Calocane, 32, who goes by the name Adam Mendes, denied murdering Webber, O’Malley-Kumar, 19, and Ian Coates, a 65-year-old school caretaker, but admitted manslaughter on the grounds of diminished responsibility due to suffering from paranoid schizophrenia. He also admitted the attempted murder of three other people who he ran over in a van. After the crown accepted his pleas, Calocane was sentenced at Nottingham crown court on Thursday. Mr Justice Turner told Calocane: “You committed a series of atrocities in this city which ended the lives of three innocent people. Your sickening crimes both shocked the nation and wrecked the lives of your surviving victims and the families of them all.” The judge said Calocane would “very probably” be detained for the rest of his life after “deliberately and mercilessly” stabbing his victims. He said Calocane’s condition was “resistant to treatment” and could not be cured, and he “remained dangerous”. Speaking outside court after sentencing concluded, the victims’ families expressed anger that Calocane had not been prosecuted for murder. “The premeditated planning, the collection of lethal weapons, hiding in the shadows and the brutality of attacks are of an individual who knew exactly what he was doing. He knew entirely that it was wrong but he did it anyway,” said Webber. It was revealed this week that a warrant for Calocane’s arrest was outstanding at the time of the attacks, after he failed to appear in court nine months earlier for an alleged assault of a police officer while he was being sectioned. Webber said: “To the assistant chief constable, Rob Griffin, I say you have blood on your hands. If you had just done your job properly, there’s a very good chance my beautiful boy would be alive today.” Griffin said he had “personally reviewed this matter” and concluded the force “should have done more to arrest him”. “In my opinion it is highly unlikely that he would have received a custodial sentence for the alleged assault,” he said. “Of course, an arrest may have triggered a route back into mental health services, but as we have seen from his previous encounters with those services, it seems unlikely that he would have engaged in this process.” James Coates, the son of Ian Coates, said Calocane had “made a mockery of the system”. “If this man was not stopped when he was this could have been one of the most catastrophic attacks this country has ever seen,” he said. “This man is a killer. Murder was the only thing he cared about and he fulfilled this in horrific fashion. All we can do is hope in due course some sort of justice is served.” Sanjoy Kumar, the father of O’Malley-Kumar, said the family had never questioned Calocane’s diagnosis, but the “missed opportunities” to divert his actions would “forever play on our minds”. “We will look for answers regarding missed opportunities to intervene and prevent this horrendous crime,” he said. Janine McKinney, of the Crown Prosecution Service (CPS), said the expert medical evidence was “overwhelming” and concluded Calocane’s actions “were substantially impaired” by psychosis caused by his paranoid schizophrenia. This gave him a legal right to put forward a partial defence to murder and offer manslaughter pleas, which the CPS accepted “after very careful analysis” of evidence, she said. “The prosecution’s case has been that Calocane was criminally responsible for what he did, as well as being impaired by his mental health.” The prime minister declined to say whether he would order a public inquiry into the matter, while saying it was an “absolutely awful case”. Speaking to reporters in Yorkshire, Rishi Sunak said it was right Calocane would “spend very probably the rest of his life” in a high-security hospital, adding: “I also think it is important that all the relevant agencies look back to ensure that all reasonable steps that could have been taken were taken and if there are any lessons to be learned that we do so.” Calocane, who studied mechanical engineering at Nottingham University, stabbed O’Malley-Kumar and Webber in the early hours of 13 June last year when they were walking home from a night out. He went on to stab Coates, who was driving to work, before stealing his van and driving it into pedestrians in the city centre. Wayne Birkett, Marcin Gawronski and Sharon Miller sustained serious injuries but survived. CCTV footage released by police showed officers tracking down Calocane in the van minutes later and using a stun gun on him as he sat in the driver’s seat before arresting him. There was an outpouring of grief across Nottingham after the attacks, with thousands of people attending vigils at Nottingham University and in the city centre to pay tribute to the victims. Ifti Majid, the chief executive of Nottinghamshire Healthcare NHS foundation trust, which treated Calocane between May 2020 and September 2022, said it had “robustly reviewed” how it handled his case, adding that staff “always aim to care for people in the least restrictive way”. Calocane was sectioned four times before the killings. After he was discharged from hospital in 2022, several attempts were made to contact him but no response was received. Webber concluded: “There is so much more to say and clearly serious questions regarding this case and events leading up to this monster being out in society.” With her voice breaking, she added: “For today, our darling son, his dear friend Grace and a wonderfully kind grandfather, Ian, have been stolen from us forever and let down by the very system that should have been protecting them.”