An NHS Trust will review 10 killings involving its patients after admitting it "got things wrong" with the treatment of a mentally ill man who stabbed a retired solicitor to death.
Matthew Daley, 35, was found guilty of manslaughter on the grounds of diminished responsibility after he knifed 79-year-old Donald Lock 39 times on the A24 at Findon, near Worthing, West Sussex, on July 16 last year. He was cleared of murder.
Lewes Crown Court heard that before the killing Daley's family had pleaded with doctors to section him, while one clinician gave evidence that he had been wrongly diagnosed with a form of autism called Asperger's syndrome.
One expert said when Daley first came to the attention of mental health teams, it was deemed he had schizophrenia, but that diagnosis was later revised to autism.
Sussex Partnership NHS Foundation Trust has apologised for its role and said it has commissioned a thematic review of 10 killings between 2011 and 2016 involving patients it had come into contact with.
The Trust's chief executive Colm Donaghy said: "We decided there was a need to look to see whether lessons or common themes from the homicide emerged.
"We believe going back five years will give us the information we need in terms of whether or not lessons can be learned.
"The review of 10 cases is not to reopen those cases - it's to look at the themes.
"The difficulty is in organisations the size of ours, over a five-year period, there can be quite a bit of turnover with our clinicians and managerial staff and so corporate memory can get lost in that process.
"I have apologised to both families and I would apologise again. I can understand the Lock family believing this is too little, too late in the context of their father and grandfather.
"It's to help in ensuring that within the organisation we do take account of the lessons to be learned. It's difficult to predict at this point - I would expect that we would find there are some themes across the homicides that we would need to take seriously."
He said there needed to be a "learning culture" within the NHS as a "blame culture" would mean staff would be less prepared to report errors.
Clinicians had primarily diagnosed Daley with Asperger's with secondary symptoms of psychosis and had considered sectioning him but decided against it, Mr Donaghy said.
Asked if the killing could have been avoided had Daley diagnosed differently, he said: "Well what I would say, we cannot say that out of absolute certainty or any high degree of certainty.
"We should have treated Matthew differently.
"NHS England now, following the outcome of the trial, will review the case - part of that review will look at whether it was predictable or preventable."
In a statement after the verdict, Mr Donaghy said: "On behalf of the Trust, I apologise unreservedly because the care we provided to Matthew Daley should have been better.
"I also want to offer my sincere condolences to the family of Don Lock and everyone else affected by this tragic, devastating incident.
"Mr Daley was referred to our services in January 2008. He received treatment from our early intervention service, which helps people who are starting to experience the symptoms of psychosis. He was later transferred to the care of one of our community mental health teams where he received treatment for a combination of Asperger's syndrome and psychosis.
"Having reviewed his care, it's clear that we should have reviewed Mr Daley's diagnosis, looked at other ways of providing treatment, done more to help him manage his symptoms of psychosis and listened to his family more closely.
"We got things wrong. But I do not believe that any of our staff acted in a way which was deliberately negligent or designed to cause harm.
"They knew Mr Daley well and believed they were doing the right things to help him. We will do things differently as a result of this tragic incident.
"The care and treatment we provided will now be subject to an independent inquiry commissioned by NHS England.
"In the meantime, we have commissioned our own independent review, jointly with NHS England, of all homicides from 2011 to 2016 involving patients known to Sussex Partnership NHS Foundation Trust.
"We have done this because we want the public, people who use our services and the organisations which commission them to be assured that we have done everything we should have in response to these tragic cases."
The report could be completed by the end of the summer this year and would be published in full, he added.
The Trust had recently introduced a digital system where patients and their carers can sign off on their care plan and family evidence can be recorded.
Copyright (c) Press Association Ltd. 2016, All Rights Reserved. Picture (c) Gareth Fuller / PA Wire.