William Barnard was originally charged with murder and attempted murder
A psychiatric patient has admitted killing his grandfather at his Nottinghamshire home.
William Barnard, 30, of Wesley Place, Stapleford, had been treated for years, Nottingham Crown Court heard.
John McGrath, 81, was stabbed repeatedly at his house on Thorpe Close in Stapleford in July 2009. His wife Mabel was badly injured in the attack.
Barnard admitted manslaughter on the grounds of diminished responsibility and will be sentenced in June.
He also pleaded guilty to a charge of wounding Mrs McGrath with intent.
Barnard had originally been charged with murder and attempted murder, but the prosecution said it would accept the new pleas as it was clear the defendant had been suffering from "a severe mental illness".
He was remanded to Rampton Hospital in Nottinghamshire.
The family said they were trying to deal with the tragedy
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