A 74-year-old man has been jailed for killing his ex-partner in his flat.
Thomas Whitehorn stabbed Rhonda Humphreys 26 times at the Trevoarn flats in Hayle, Cornwall, on 25 October, Truro Crown Court heard.
He had tried to help the former RAF sergeant, but her alcoholism and other problems made him go "mad", and he suffered depression, the court heard.
Whitehorn admitted manslaughter by diminished responsibility and was jailed for nine years.
Prosecutor Jo Martin QC said Whitehorn had lived in his flat since 1998 and his victim in a flat above since 2003.
They became friends and previously had a relationship, but she also had mental health issues, the court heard.
Whitehorn, who had had depression and other health issues, including anxiety, was also suffering from stress because of antisocial behaviour from a downstairs neighbour since 2017, the court was told.
Whitehorn, who collected military memorabilia, including knives, put what he told police was a "commando knife" in a drawer and stabbed Ms Humphreys in her head, neck and face when he "just went mad", the court heard.
He called emergency services, telling them Ms Humphreys had been "doing my head in with rubbish talk", and he wrote on walls and in a letter that he was no danger to anyone but the 53-year-old was "evil".
After killing her, he attempted to kill himself with an overdose of tablets.
Mitigating, Andrew Langdon said the pair had cared for each other but he had been "unable to cope in recent years" and that "stopped him being rational".
Sentencing, Judge Simon Carr told Whitehorn "nothing can justify the action you took" in killing this vulnerable victim.
However, he said he took into account Whitehorn's age, previous impeccable character, and that there had been "no doubt you attempted to help" Ms Humphreys.