The mother of one of the victims of the knife attacks in Nottingham on 13 June last year has said she was "foolish to trust the legal system" after the killer was sentenced to detention in a high-security hospital.
Emma Webber, whose son Barnaby Webber, 19, was stabbed to death along with Grace O'Malley-Kumar, also 19, and Ian Coates, 65, said she was "ill-prepared" to find out the killer's manslaughter plea had been accepted.
"I feel now with hindsight that I was foolish to just trust in our legal system. And I hate to say that, because I do feel let down," she told Sky News presenter Sarah-Jane Mee in an interview alongside her husband David.
"We were led to believe all of summer that it would be a murder charge for our son and the other two victims, and then attempted murder for the other three victims.
"It's a massive, heinous crime. So we were ill-prepared for being told... that they were going to be accepting a diminished responsibility, which meant manslaughter. And I think that was the moment that everything turned."
It comes as a special review has been ordered by the government into the NHS trust where the killer, Valdo Calocane, was treated.
Calocane stabbed Mr Webber, Ms O'Malley-Kumar and Mr Coates and then tried to kill three others with a van in Nottingham on 13 June 2023.
The 32-year-old, who has paranoid schizophrenia, was sentenced to detention in a high-security hospital after prosecutors accepted his manslaughter plea rather than pursuing a murder conviction.
He had been detained in hospital four times under mental health laws before the attacks.
Now, Health and Social Care Secretary Victoria Atkins has ordered a special review into Nottinghamshire Healthcare Foundation Trust, where Calocane was treated.
The review will provide further answers for the families of the victims and focus on wider issues in mental health care provision in Nottinghamshire, including at Highbury Hospital and Rampton Hospital.
Conducted by The Care Quality Commission (CQC), it will be carried out alongside the Independent Mental Health Homicide Review ordered by NHS England to examine the case of Calocane.
The CQC, which will have access to witness statements and evidence regarding health services which were called on during the criminal trial, will present its findings on patient and public safety, and on the quality of care provided across the trust in March.
The government will then issue its response to the review in due course.
Confirming the review, Ms Atkins said: "My thoughts remain with the families and friends of Barnaby, Grace, and Ian, who lost their lives in such a tragic, cruel and barbaric way.
"It is crucial that our mental health services ensure both the care of patients and the safety of the public.
"I hope the review provides the families and public with some much-needed answers, and that it helps the trust to improve the standard of mental health care in Nottinghamshire."
The director of mental health at CQC, Chris Dzikiti, said the public body would conduct a "rapid review" into mental health services in Nottingham to "understand whether there are any practical actions which can be taken to improve the quality of services and ensure people receive safe and effective care".
Meanwhile, Claire Murdoch, NHS national mental health director, added: "NHS England is commissioning an independent investigation into the case, and we will cooperate fully with the government's review of the trust's mental health services, while continuing to provide the trust with intensive support to protect patient safety in partnership with the CQC."
Last week, the victims' families criticised Calocane's sentence - as well as authorities they say could have prevented the tragedy.
A spokesman for attorney general Victoria Prentis, the government's chief lawyer, confirmed a referral had been received.
She will now have to decide whether to refer the case to the Court of Appeal for judges to decide if the sentence is appropriate.