Peter McShane drilled holes in neighbour's roof
An 86-year-old man clambered onto his neighbour's roof and drilled holes to let in the rain as part of a feud, a court was told.
Ex-soldier Peter McShane climbed onto the roof of the property in Pembroke Dock in darkness armed with a drill and other tools, magistrates heard.
The drilling caused £3,000 of flood damage the next time it rained.
McShane admitted criminal damage and will be sentenced at Haverfordwest Magistrates' Court at a later date.
The court on Monday heard that McShane started drilling through the roof while his neighbours were away from home.
Magistrates heard McShane, who needs two walking sticks, admitted to police he was "barmy" at the time, and had even blocked up guttering to increase the rain flow into the property.
David Weale, prosecuting, said: "It was a deliberate and conscious act. He is no fool and knew this would cause water damage.
"The neighbours found water running down the walls of their property and some electrical goods were damaged."
Mark Layton, defending, said: "It was part and parcel of a broader number of issues that were troubling Mr McShane.
"He never came to the court's attention until he was in his 80s.
'Bitter and resentful'
"Old age affects people in different ways but in Mr McShane's case he seems to have become bitter and resentful."
Last year, McShane received a 34-week suspended jail sentence and a curfew order after he admitted making a bogus bomb and seven other charges.
He planted the hoax bomb outside an NHS dentist in Pembroke Dock after he was charged £183 for dental work in 2007.
Dozens of homes were evacuated and traffic diverted while army bomb disposal experts arrived to examine the package.