Three patients who killed three men in separate attacks in Bristol were all being treated by the same mental health partnership, reports have said.
The men were all convicted of separate homicides committed in 2008, North Somerset and Wiltshire while receiving care from Avon and Wiltshire Mental Health Partnership NHS Trust.
The three independent reports each identified "no direct causal factors" between the care and treatment the three men received and the killings.
James Allen was convicted of murdering his neighbour Terry Hall during a row over a discarded washing machine. Liam Churchley was jailed alongside his mother, brother and cousins for the savage killing of Alan Riddock outside a pub, while James Bible was detained indefinitely for stabbing his friend to death.
All three had been receiving treatment for a variety of problems, including drug and alcohol addiction and psychiatric disorders.
While the reports highlighted aspects of care that could have been better, each report concluded that it would "not be reasonable" to conclude that these had an impact on each incident.
A total of 28 recommendations are made in the separate reports, of which 22 relate to the Avon and Wiltshire Mental Health Partnership NHS Trust.
Dr Arden Tomison, medical director for the trust, said: "The investigation reports acknowledge the considerable efforts made by our staff to support each service user in the years leading up to the incidents.
"Across the Trust our staff deal with individuals whose complex needs, behaviour and reluctance to be helped can make delivering effective care support very difficult. The decisions our staff make about the care and support provided to service users are informed by the best clinical understanding of their individual clinical needs.
"I would like to thank all our staff for their dedication and commitment in supporting people under our care and reassure people that the risk of any act of violence being carried out by a person with mental health needs is very small."