Mana, an 8-month-old black Labrador, was unclipped from his chain and snatched from his owner's St Kilda property on Monday night.
"I went out to feed him after watching Shortland Street, and he was gone," owner Horiana Clarke said.
A frantic two-hour search proved fruitless, and just minutes after Ms Clarke returned home, her daughter heard a car door slam outside at 9.30pm.
"I went to the window and there was the dog at the doorstep. He was heavily traumatised, bleeding from the neck and jaw area [and] his eye has been bitten."
Ms Clarke said she believed the dognapper set a "vicious" dog or dogs on the puppy, and it might have been involved in an organised dogfighting event.
Mana was later taken to the vet, who noted teeth marks and, torn skin from under his jaw and eye. The dog was given injections and antibiotics.
She said those people who took her puppy should know "what goes around come around".
"There was no need for it. He is an innocent puppy that would not hurt a fly.
"They [the dognappers] have a sick head."
Senior Sergeant Steve Aitken said he struggled to "understand the mentality of the people who would allow a dog to be injured in such a way".
Inquiries were continuing and anyone with information is urged to contact Dunedin police.
