A judge has said mental health doctors in Nottinghamshire should "examine their consciences" after a paranoid schizophrenic stabbed his grandfather.
William Barnard, 30, of Wesley Place, Stapleford, inflicted 56 wounds on John McGrath in July 2009. His wife Mabel was badly injured in the attack.
Nottingham Crown Court was told mental health workers did not respond to pleas for help from Barnard's family.
Barnard has been committed to Rampton high security hospital indefinitely.
He admitted manslaughter on the grounds of diminished responsibility at an earlier hearing, and also pleaded guilty to a charge of wounding Mrs McGrath with intent.
Barnard was originally been charged with murder and attempted murder, but the prosecution accepted the pleas as it was clear the defendant had been suffering from "a severe mental illness".
In sentencing Barnard, Judge Michael Stokes QC was highly critical of Nottinghamshire's mental health services.
He said: "It's clear there had been numerous opportunities to send [William Barnard] to hospital and it is a matter of grave concern that these opportunities were missed repeatedly."
He added that those responsible for William Barnard's care should be "examining their consciences".
In a statement, Nottinghamshire Healthcare NHS Trust said: "The trust has undertaken a detailed internal investigation to review its involvement in the care of the person involved in this case who had been receiving input from community services for approximately seven years before this incident.
"This investigation has revealed that the general level of care provided to this patient during 2009 fell below an acceptable standard and for that we are very sorry.
"The findings from this review will be reported to the trust board and there will be a swift and diligent response to the recommendations."