The death of a boy who was drowned in the bath by his grandfather could have been avoided, a report has said.
Stewart Greene killed nine-year-old Alex Robinson two days before Christmas in 2014 at the family home in Lincoln.
Greene, who was jailed for life in 2015, had been discharged from a mental health unit less than two weeks before the murder.
Alex's family said he had been "hurriedly discharged" because of his repeated violent behaviour on the ward.
The independent report, commissioned by NHS England, said Greene, referred to as Mr T in the investigation, had a long history of involvement with mental health services dating back to 1991.
It found that although there was evidence of violence and threats towards staff prior to his release, it was not possible to predict the escalation in his behaviour which led to Alex's death.
"We do however consider that there were actions that trust staff could have taken that might have avoided Mr T killing Alex," the report said.
It said his discharge had been "rushed" and there was "no clearly documented rationale or discussion leading to the sudden decision to discharge him".
In a statement, Alex's family said: "We remain concerned and angry that Alex's death was entirely preventable - had the numerous and repeated failings documented in this report not occurred.
"A dangerous, mentally ill man was hurriedly discharged from hospital into the community because of his repeated violent behaviour on the ward.
"He told medical staff he heard voices telling him to 'hurt people' and even tried to strangle a doctor.
"He was then knowingly discharged into the care of our young family with children who were not told about his serious violence in hospital."
The report makes a number of recommendations for the Lincolnshire Partnership NHS Foundation Trust (LPFT) - which ran the unit - and for local clinical commissioning groups around improving the discharge process.
Anita Lewin, LPFT's director of nursing, allied health professionals and quality, said: "On behalf of our trust, I would like to say how very sorry we are about Alex's death.
"We welcome the publication of today's report, which makes a number of recommendations, all of which have been acted upon and completed.
"We note the finding in the report about the importance of listening to the views of the family and we now have a clear programme in place to support our staff to listen to family members and carers, involving them as partners in care."