The region's mental health trust has insisted it repeatedly reported murderer Alex Palmer to police and other organisations before he killed dog walker Peter Wrighton.
It comes after Palmer's parents yesterday claimed their warnings their son was not taking his medication were ignored by doctors because they could 'only believe the patient'.
Speaking to the BBC Palmer's mother and stepfather, who did not want to be named, said Norfolk and Suffolk Foundation Trust (NSFT) had 'missed chances' to prevent the murder of 83-year-old Mr Wrighton, who Palmer murdered in East Harling in August.
MORE: 'He said he was going to kill' - Parents of East Harling murderer claim they warned mental health workersHis mother said: 'They thought we were busybodies, interfering in Alex's mental health and care, because they were the experts.'
But a spokesman pointed to a statement given when 24-year-old Palmer, from Cringleford, Norwich, was jailed for life in February, which said: 'Although the trust cannot comment on any treatment advice which Mr Palmer was given, the trust can confirm that staff did, on more than one occasion, liaise closely with other organisations including the police to raise concerns.'
MORE: Peter Wrighton killer Alexander Palmer jailed for lifeAnd yesterday the trust's new chief executive Antek Lejk said an independent review was taking place. He said: 'I've got enormous sympathy with anyone who has to go through those sort of experiences.
'I can't comment on the detail because we are carrying out a review of what happened, we will pay attention to those lessons and I did notice Mr Palmer's stepfather was saying very reasonably and fairly that internal reviews don't often get to the truth. Well we're not doing this to hide away from the truth, we want to make sure any lessons to learn are learned.'
On carers' involvement in treatment he added: 'It has to be on a case by case but carers are a phenomenal resource who help people stay healthy.'
MORE: Face of a killer - Alexander Palmer took selfie shortly after murdering Norfolk grandfatherDuring Palmer's trial the court heard how he suffered mental health problems following a head injury from being attacked on a night out in Plymouth in 2013.
He told mental health professionals about voices in his head which told him to hurt people, particularly dog walkers.
Speaking afterwards Mr Wrighton's daughter Carol Todd and son Andrew Wrighton said: 'The revelations of the evidence relating to the mental health of Alexander Palmer have shocked, astounded and angered us.
MORE: How a phone call from a psychologist led police to killer'We feel this should not have happened and mental health professionals failed him, his family and our family.
'My mum, brother, myself and our children not only feel grief but anger, as we believe this crime could have been prevented.'
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