An "evil" 85-year-old man who murdered his neighbour with a spade while he slept has been jailed.
Thomas Dunn has been sentenced to life with a minimum term of 17-and-a-half years for the "cowardly" killing of retired army engineer Royston Costello.
Dunn formed a "grudge" against "gentle giant" Mr Costello after claiming he had been breaking the rules at Oakdene Court sheltered accommodation complex in Sandbach, Cheshire, where they both lived, a court heard.
The killer alleged that the victim, a father-of-two who had six grandchildren, had been letting his dog off its lead as well as making noises and using a fire door.
He was also unhappy Mr Costello, 60, had been given a new car under a mobility scheme.
Mr Costello denied any wrongdoing but woke up on 19 February to find a Z mark had been scratched on to his car.
He confronted Dunn and complained to police, who launched an investigation.
The stand-off prompted Dunn to "carefully plan" an attack on Mr Costello, taking a spade from another resident's shed the following day, in the early hours of the morning, Chester Crown Court heard.
He waited until Mr Costello's wife Cathy took the dog for a walk - leaving Mr Costello alone in his flat, sleeping on the sofa.
He then bludgeoned him on the head three times, purposely using the side of the spade to inflict the most harm, before dumping the weapon in a hedge and riding off on his mobility scooter.
Mr Costello suffered a smashed skull and was discovered with serious head injuries by his wife when she returned around 10am.
He was taken to Royal Stoke Hospital where he underwent emergency brain surgery and was placed in critical care, partially paralysed and unable to speak.
But despite the efforts of medics, he died two months later on 20 April.
Dunn was located by police on the same day of the attack inside another nursing home in Wilmslow, Cheshire.
He told officers he wanted to "belt" his victim and admitted he knew he had inflicted serious harm to Mr Costello with the first blow - but hit him again twice to "teach him a lesson".
Dunn - who has prostate cancer - was charged with murder after Mr Costello died and he pleaded guilty last month.
Passing sentence, Judge Steven Everett, the Honorary Recorder of Chester, described the attack as an "appalling act of violence" and "incredible cowardice".
"It is utterly mystifying to me why an 85-year-old would come to commit this terrible attack," the judge said.
"But your behaviour is consistent with being a difficult, rather arrogant, aggressive and mean-spirited person.
"It may be that your illness will take you much sooner than the minimum sentence."
Speaking after the hearing, Mrs Costello described how her husband's death had left a "big void" in her life - and branded the killer an "evil coward".
She said she would "always love" Mr Costello and thanked him for the "wonderful 23 years" they shared together.
"Roy and I were very much one unit and we went everywhere and did everything together, quite simply we were each others world, we always said as long as we had each other that was enough," Mrs Costello said.
"I miss Roy each and every day and I now have to live my life a different way, I will do my very best to live a life without Roy as I know this is what he would want, but I do not look forward to this and it will not be easy without him, he was my rock."