On April 16, he and his partner arrived at the facility and Murdoch asked to be let inside.
A staff member refused and they spoke for a bit before Murdoch licked his fingers and wiped them down the reception window.
He also made a display of rubbing his hands across the handle of the entrance door.
During the hearing last year, it was reported Southern District Health Board had cleared him of Covid-19 that day.
On April 17, he arranged with his supervisor to return to work the following week, but his partner became unwell again and he was told to not return to work until she had been cleared of the virus.
On April 22, Murdoch and his partner returned to the animal care facility and again he asked to be let into the building.
After being refused entry, he did the same thing - breathed on and licked his fingers and wiped them on the same window.
However, this time, he also did it on his colleague's car door handles.
Invercargill City Council dog controller officer Jo Anne Michelle Cockcroft read a victim impact statement and said she wasn't angry with Murdoch at the time, but was disappointed.
"I'm certain he did what he did without malice and I don't think he was even aware at the time how his actions could potentially affect the facility."
She had elderly parents and she had a "real fear" she could have contracted the virus and put her parents and other people in danger as he was an essential worker.
Cockcroft said it affected her mental health.
Police prosecutor Marcus McMahon said Murdoch's actions were against everything the country was trying to do to combat Covid-19.
Defence lawyer Olivia Taylor said a conviction would make it difficult for Murdoch to obtain any employment in the country.
A letter from his doctor stated he suffered mental and health issues after his visits to his workplace.
Judge Walker acknowledged Murdoch had shown remorse and shame from his action but was not satisfied the consequences would be "out of proportion" for the offending and denied the application for a discharge without conviction.
Judge Walker convicted Murdoch and described his behaviour as "an astonishing lapse of judgment", but as he had already lost his job and suffered health issues, he would only apply a fine.
"Your behaviour was juvenile," he told Murdoch.