A public inquiry into the Nottingham attacks revealed a "catastrophic collapse of responsibility" and an "undoubted miscarriage of justice", the mother of one of the victims has said.
Valdo Calocane, who had been diagnosed with paranoid schizophrenia in 2020, stabbed to death Barnaby Webber, Grace O'Malley-Kumar and Ian Coates, and tried to kill three others in Nottingham on 13 June 2023.
The lead-up to the attacks and the aftermath were scrutinised during a 14-week public inquiry, which concluded on Friday.
Speaking at a press conference in London on Monday, Barnaby's mother Emma Webber said: "It has been brutal, bruising and harrowing beyond measure - but it was so very necessary. "
Emma added there had been "cover-up over candour".
She said: "This wasn't bad luck. It was a catastrophic collapse of responsibility. An undoubted miscarriage of justice that must now be addressed."
Emma is calling on the government to meet the families within the next month, adding they would be calling for "urgent re-examination".
She said: "The findings of this inquiry will not be made until spring of next year, however, that does not prevent action from being taken now.
"This isn't about vengeance, it's about doing the right thing."
She added: "Excuses stop here and accountability starts today."
The Nottingham Inquiry - the hearings of which began on 23 February, heard from 164 witnesses and ended last week - laid bare a series of failings by authorities, including the NHS and police, in the years leading up to the attacks and in the aftermath.
Calocane is currently serving an indefinite hospital order after pleading guilty to three counts of manslaughter on the grounds of diminished responsibility, and three counts of attempted murder in relation to survivors Wayne Birkett, Sharon Miller and Marcin Gawronski.
The bereaved families have maintained the attacks were avoidable and never been happy with Calocane's sentence.
Now oral evidence has concluded, the core participants of the inquiry will share closing statements at hearings in September, before the chair of the inquiry - retired senior judge Deborah Taylor KC - is expected to release a report with her recommendations next year.
Ian's son, James Coates, said for "what felt like a very long time", he and the other bereaved families believed "institutions did everything they could".
"Unfortunately, we were delusional in our belief that justice would be served," he added.
"For two and a half years, we've watched organisations close ranks, mark their own homework, and the inquiry must be the true reckoning."
Barnaby's father, David Webber, said: "I can't get to my death bed without change.
"How many people need to die? How many people need to be assaulted for change to happen?"
He added: "We're fighting on to do what's right for our loved ones. Without sounding too glib, we're here to push on for the betterment of the country.
"This can't continue. We're seeing it more and more and more and it's just got to stop."
The public inquiry heard how staff at a number of organisations, including Nottinghamshire Police, inappropriately viewed records or information related to the fatal attacks.
In May, Nottingham University Hospitals NHS Trust confirmed it had dismissed 11 members of staff for inappropriately accessing medical records, while 12 had received final written warnings and two had first written warnings.
The Independent Office for Police Conduct launched five investigations into police forces after the attacks.
During the inquiry, the director general of the policing watchdog admitted it had "let down" the affected families.
The former chief constable of Nottinghamshire Police, Kate Meynell, admitted in her evidence that Calocane should have been arrested before he killed Barnaby, Grace and Ian.
A warrant for his arrest was issued in September 2022, after he failed to appear in court for assaulting PC Barnaby Pritchard. Calocane had attacked him a year earlier while he was being detained under the Mental Health Act.
Calocane was in hospital when he was due to appear in court after being sectioned on another occasion. However, police had nine months to execute the warrant.
Police bosses admitted not arresting Calocane had been a "serious and systemic and operational failure".
Dr Sanjoy Kumar, Grace's father, said it was "perhaps the biggest missed opportunity".
At Calocane's sentencing hearing in January 2024, the court was told he had no previous convictions.
However, the inquiry heard he had a history of police interactions linked to violent incidents, including the assault on Pritchard, dating back to 2020.
In May 2020, Calocane was experiencing a psychotic episode when he kicked in the door of a woman's flat at Brook Court in Radford.
The woman fell from the window as she attempted to flee and was left needing metalwork and screws surgically fitted to her spine.
She said a police officer told her Calocane could not be prosecuted at the time because of his mental health.
Speaking at the press conference, Lee Coates - Ian's son and James's brother - said: "I think if people did their jobs properly back in 2020, we wouldn't be sat here now."
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