Keir Starmer today committed to a judge-led inquiry into the Nottingham attacks if Labour wins the General Election.
The Labour leader's promise comes after calls from grieving families who have said there were "missed opportunities" to prevent the victims' killings.
Grace O'Malley Kumar and Barnaby Webber, both 19, and Ian Coates, 65, were all fatally stabbed by Valdo Calocane, a paranoid schizophrenic, in the early hours of June 13 last year. Calocane was given a hospital order after pleading guilty to manslaughter by reason of diminished responsibility back in January.
During an LBC call-in, the Labour leader was played a voice message from Emma Webber - the mother of 19-year-old Barnaby. She asked Mr Starmer if he enters No10 next month for his thoughts about "following through with the call for a public inquiry, or possibly a judge-led inquest".
"And also your thoughts please on the urgent need to reform our homicide laws and also the victim support in this country? Which from bitter experience, I can confirm is woeful and very inadequate," she added.
Brit 'saw her insides' after being cut open by propeller on luxury diving tripThe Labour leader replied: "Just a horrific experience that she and all the family members and friends have been through, and she wants a judge-led inquiry and I said when I met her that I thought that was the right way forward, and we would do that."
He added: "I was very concerned when I heard from her directly about the way the system had let her and the other family members down in relation to the charges that were brought, the communications with the family, and so many other aspects.
"And my resolve is to ensure that we have that inquiry and make sure that that doesn't happen to anyone else. I've had too many examples of victims and family members being let down. We have to improve here."
In an interview with The Mirror last week ahead of the anniversary of the attacks, Ms Webber said her family had been "completely blown apart". She added: "The past 12 months have been like being in an alternative universe. Everything in our normal lives has completely changed."
Earlier this year Dr Sanjoy Kumar - the father of Grace - said it was in the "public interest" for an inquiry to be held so people can be "held accountable for all the failings" in the case.
He said: "I want to have people held accountable for the failings - I want physicians who have failed their patient, the laziness of the police to be called out, I want to find out where things could have been stopped. What does it take to get the services working the way they need to?"
Nottinghamshire Police have previously said there is an ongoing "independent investigation into complaints raised by the families of Valdo Calocane’s victims".