Reviews of two killings by people with mental health problems in Wales have found shortcomings in their treatment and care.
Common failings between the cases include a lack of co-ordination of services and communication between different agencies, the Healthcare Inspectorate Wales found.
Wayne Royston was jailed for murder after stabbing 21-year-old Dean Shorney 38 times in April 2006 in a park in Bargoed, Gwent.
Mr Royston, who was well known to mental health services, had shown a "high risk of serious violence", the report said. The review found "system failures" around his diagnosis, care management and multi-agency involvement.
Caerphilly teaching local health board, Gwent Healthcare trust and Caerphilly county borough council said they would strive to improve joint working.
In a separate case, Deborah Hancock admitted manslaughter on grounds of diminished responsibility, after knifing 75-year-old Valerie Thomas in a shop in Cardiff city centre in October 2005. The report said the services Ms Hancock, who was diagnosed with a borderline personality disorder, received were "less than optimal".
It highlighted the need for better management of joint working between health and social care in community mental health teams.
It said: "Senior managers in both organisations need to take responsibility for ensuring that good relationships result in common strategies, protocols and the will to provide well co-ordinated and [where appropriate] integrated, services."
Cardiff local health board, Cardiff county council and Cardiff and Vale trust's joint statement says since the incident "specific changes in assessments, care planning and communication" had been made.
NHS Wales chief executive Ann Lloyd said there had been "considerable progress" in mental health services since the tragedies.
The recent findings will feed into a review of secure services in Wales due to report back later this year.
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