A man described as "clearly" having mental health issues broke into the RSPCA to save his cat before realising it was a different animal, leading to a Canberra-wide search for escaped felines Beau and Luna.
In other incidents, the Weston resident spat at or near a police officer and threatened to kill his "paedophile c---" neighbour while holding a knife.
Adam Leslie Munday, 40, captured on CCTV footage as spending more than four hours at the Canberra RSPCA shelter in the early hours of April 17 last year, said he was looking for his cat which had been missing for six months.
"He observed a cat that looked like his missing cat and subsequently smashed the window to the cat shelter to confirm if the cat was his or not," a police document tendered to court said.
"As he did this [another] cat jumped out the window and ran off. [Munday] realised the cat wasn't his and left the enclosure."
RSPCA staff turned up to work the next morning to find the Tangos Cat Boarding Facility had a smashed window with a bent frame and blood stains.
Police also found a bag of bread, a tub of butter, a silver multitool and keys with a red tag.
Following the break-in, RSPCA ACT called for public assistance in finding the cats and ACT police released CCTV footage of Munday walking into the shelter.
At the time, RSPCA ACT CEO Michelle Robertson wrote on social media, "it is with a pleading heart that I ask for your help.
"Someone violently smashed, shattered and forced their way into one of Tangos Cat Boarding Facility suites.
"The family is shocked and deeply saddened. Our hearts are breaking with them."
In a statement to The Canberra Times, the RSPCA ACT said the break-in "shook our entire team of staff and volunteers".
"It was a devastating experience, and our hearts broke along with the family of Beau and Luna ... [the perpetrators] actions caused so much distress."
Luna was found in late May in a humane cat trap, while Beau was only found in November in Curtin by a family friend of his owners.
Both cats were previously adopted from the RSPCA and were in the boarding facility while their family was on holidays.
On Wednesday, Munday was sentenced to 18 months in prison at the ACT Magistrates Court for six charges over three separate events.
This included damaging property and burglary with an intent to steal regarding the RSPCA incident.
On the evening of January 16, Munday walked to the carpark of his unit block in south Canberra wearing only underwear and holding a beer bottle while "unsteady on his feet and swaying from side to side".
Munday banged on the bonnet of his neighbour's car, leading to what was described by Magistrate Ken Archer as an "interchange of unpleasantries" between the pair.
According to court documents, Munday punched the neighbour in the head and the two engaged in "an amicable physical altercation".
About 20 minutes later, the barely-clothed Munday approached the neighbour holding a 30-centimetre knife and said "I'm going to kill you".
Munday called the neighbour a "pedophile c---" and told him "tomorrow at six I'm going to murder you".
The victim said he feared for his and his son's life as he thought Munday would jump the fence with the knife.
Munday has pleaded guilty to threatening to kill another person and possessing an offensive weapon with threat to kill for the carpark incident.
Munday was also charged over an indecent act towards a police officer.
Police came across Munday in September last year drinking while "indiscriminately yelling swear words" at City Walk in Canberra City.
Munday had shattered a glass bottle on the ground and had a physical fight with a member of the public.
The sobering up shelter was closed, police said in court documents.
They said they made numerous requests for Munday to nominate a responsible adult, but he "instead repeatedly told police to 'suck a dick you paedophiles'".
An officer asked Munday if he lived with anyone to which Munday replied, "suck a dick you child molester".
He pulled down his pants down and exposing his flaccid penis, holding it for four seconds while staring at the officer.
Munday was taken into City Police Station where he was asked to wear his face mask.
He then either spat at the police officer or at a counter.
Mr Archer said "either way the spit landed on [an officer's] forehead and was later observed to be on other parts of his clothing."
The police officer said he felt "immediately disgusted".
Munday pleaded guilty to an act of indecency and assaulting a police officer.
Mr Archer described the act as "blameworthy and in any sense, hard to forgive" as the police seemed to have dealt with Munday "with great patience and forbearance".
In his sentencing remarks, Mr Archer said "clearly it seems to me [Munday does] suffer from mental health difficulties".
"He has been brought up in a violent [and abusive] environment and that has had a long lasting effect."
Munday had previously been diagnosed with anxiety, depression and cyclothymia, but Mr Archer suggested there may be other undiagnosed mental health conditions.
A pre-sentence report assessed Munday as at a high risk of re-offending.
Munday was sentenced to 18 months in prison.
Half the sentence is suspended, meaning Munday will serve a minimum of nine months behind bars.