Her desperate measures came after reporting the "heartbreaking" theft to police, dog control and SPCA, who all came up empty-handed.
Within days, she received a letter from Christchurch police saying they "can't proceed any further with this case".
"After looking at all the available evidence we have not been able to find out who is responsible," it said.
The letter astounded the 40-year-old sales and events co-ordinator, who wondered what "evidence" they could have considered, since no officer visited her Shirley home.
Police confirmed that no one had looked at the case in depth.
"We're swamped with files like this," said Sergeant Tony Tully of Papanui station.
After her case was publicly highlighted, police told Ms Berney that the suspected thief was living in Oamaru.
"The Oamaru cops were really good. They went round and checked out the address, but obviously the guy had the dog hidden somewhere," Ms Berney said.
But she was no closer to getting Oscar back, until she received an anonymous tip that the dog was definitely still at that Oamaru address.
Ms Berney then contacted local dog control, who took up the crusade.
"One day a dog control officer saw Oscar and told police, who executed a search warrant. Even though no one was home, they broke in and got Oscar back."
She immediately drove down to collect him last Thursday.
"I was ecstatic. He's really happy to be home - he jumped straight back in his own bed."
Oamaru police told Ms Berney that the man was going to be charged with receiving stolen goods.
