It's understood that in February, 2018, Brotherson confronted Bilijon and his then-girlfriend and accused them of stealing from him.
The couple then began packing their car with belongings, including their two dogs Turbo, a 10-month-old kelpie cross and Nova, a bull terrier cross.
But Brotherston wanted to exact revenge and used a filleting knife to slice Turbo's throat.
The couple rushed both dogs to a nearby vet, but Turbo was pronounced dead on arrival.
Appearing at the North Shore District Court, Brotheron was sentenced to two years jail.
He was also disqualified from owning animals for seven years and ordered $1742 in vet fees, $1000 in reparation and $500 to each victim.
Speaking about the sentencing, Bilijon said he was pleased about the outcome.
'It's probably the best outcome that Casey and I, and all of us, could have asked for,' he said.
Bilijon added that Casey still owned Nova, but he himself had not been able to bring himself to get another dog and still had a lot of 'trust issues' following the horrific incident.