A report was made to the police, and the Veterinary Association asked its members to alert them to any pregnant Boston terriers brought in to clinics, or puppies born around May 30.
Three months later, a vet in Palmerston North, 48km away, notified the association about a 7-week-old Boston terrier pup brought in for vaccinations. The vet took the dog's DNA.
Police interviewed the owners, who had named her Poppy.
A court summary of facts said Thomas Leroy Gray, 37, who had previously appeared before the courts, had in April taken Essie - valued at $2800 - back to his home in Palmerston North, where she had given birth to at least two puppies, worth $2000 each.
In July, he sold one of the puppies to an "associate" for $200.
In August, he admitted to the police that he had been in possession of an adult Boston terrier and three puppies, but said he no longer had any of the dogs.
Essie's owner told the Herald her breeder had kept a copy of her DNA on file, so the owner couriered it and Poppy's DNA to a laboratory in Australia. The result was a match, and she took the results to the police.
According to the summary of facts, Gray's home was searched on November 19 and a male Boston terrier puppy was found. But there was still no sign of Essie.
The owner said that after the raid, police officers were speaking about the case back at the station.
A community constable from the Palmerston North suburb of Highbury remembered seeing Essie at a home a few months earlier.
The woman who had her said she'd rescued her from a house where she had been tied up with such a heavy chain that she could not lift her head.
She nursed the dog back to health.
Essie was returned and the male puppy has been rehomed. Poppy is still with its new owners.
Last week in the Palmerston North District Court, Gray was sentenced to two months' community detention and 180 hours' community work and ordered to pay $6000 in reparation after pleading guilty to receiving property worth more than $1000.
The owner said it took a few weeks for Essie to settle back into home but she was doing better.
"She's a very important member of the family and important to my girls. She comes to work every day."
Callum Irvine from the Veterinary Association said "DNA profiling of animals is relatively new - but it's just like testing humans' DNA, it's highly accurate."
Deslie Blanch, secretary of New Zealand's Boston Terrier Club, said breeders often kept copies of the dogs' DNA to protect bloodlines.
Boston terriers
• Thought to be around 500 purebreds in NZ.
• Can cost up to $3000 each.
• Owners sign contracts with the breeder saying they won't breed the dog with another breed, to protect bloodlines.
• DNA profiles of each dog often kept.
