James Allen attacked 81-year-old Colin Dunford in his Middlesbrough terrace home, then three days later stabbed Julie Davison, 50, to death at her flat in Whitby, North Yorkshire.
The double killing sparked a huge manhunt which ended in Leeds when an off-duty police officer spotted him.
Allen, 36 at the time, was convicted of murdering his vulnerable victims in April 2012 after a trial at Newcastle Crown Court and was jailed for at least 37 years.
At the time of the offences, Allen was receiving care from Tees, Esk and Wear Valleys NHS Foundation Trust, a provider of mental health services.
As a result NHS England commissioned an independent investigation by Niche Patient Safety into the healthcare and treatment provided to Allen, referred to in the report as Mr F.
Making a number of recommendations, the report concluded that “there were many deficiencies and missed opportunities by both primary and secondary health care services where important information could have been sought and shared”.
“If obtained, this information would have enabled a more accurate assessment of Mr F’s risk factors and would have alerted agencies to his potential for re-offending,” it said.
It went on to say that “there was enough evidence to indicate that Mr F was a vulnerable individual who had significant known risk factors”.
“Therefore, it was Niche’s opinion that services should have identified that there was a significant probability that he would re-offend. What was not predictable was Mr F’s choice of victims in this tragic double homicide,” it said.
It found Allen had been over-prescribed the drug pregablin, that no mental health agency had sought to obtain information regarding his forensic history and, as the prison service does not release a prisoner’s medical notes on release, primary care services were unaware of his full history.
It also concluded that despite him repeatedly reporting his fears of a relapse in his mental health, no agency considered the potential psychological effect of Allen’s chronic health condition on his mental health.
Karen Conway, head of investigations for NHS England North, said: “The circumstances surrounding the tragic death of these two victims are extremely upsetting and our deepest sympathies go to their family and friends.
“It is clear that the care provided to Mr F [James Allen] could and should have been better and fell well below expected standards. The report rightly highlights a number of issues around roles, responsibilities and working practices which must be resolved for positive progress to be made.
“As commissioners of GP services in the region, we will be ensuring that all recommendations relating to primary care are implemented and embedded into general practice.
“The mental health trust needs to scrutinise fully the areas highlighted for improvement to make sure all the recommendations are implemented, and that positive progress is clearly demonstrated.”