The parents of Alexander Palmer, a former soldier who stabbed a pensioner to death in East Harling, have said they warned mental health workers he was collecting knives.
Palmer, 24 of Freesia Way, Cringleford, was sentenced to life in prison with a minimum term of 28 years in March, after being found guilty of the murder of 83-year-old Peter Wrighton last year.
He stabbed the grandfather more than 44 times as he walked his dog on August 5, 2017.
In an interview with BBC Look East, Palmer's mother and stepfather - who did not want to be named - claimed they made Norfolk and Suffolk NHS Foundation Trust's mental health team aware of both Palmer's knife collection and his intention to kill.
Palmer's mother said: 'He was told by the case worker: 'look, you're 24 and living at home - move out, get a job, get a life'. That was their answer to his mental health issues, even though I was going: 'by the way, he has a selection of knives'.
'He said he was going to kill somebody and how and said it was inevitable. He said it himself.
'Maybe we should have done more, but the amount of times we were treated like we were interfering - like I wasn't the expert so what did I know?
'They (mental health professionals) thought we were busybodies, interfering in Alex's mental health and care, because they were the experts.'
Palmer's stepfather added the pair were made to feel 'insignificant'.
He added: 'Peter Wrighton paid the price and his family continues to do so.'
The Trust has said an internal review into the case was under way, with results likely to be published in the summer.
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