Russell Mendoza this week entered his neighbour Rowan Hargreaves' Wellsford property with another man and killed 23 puppies and 10 adult dogs, adamant one or more of them had mauled his fox terrier days before.
The small dog subsequently died.
SPCA investigators broke down yesterday as they described the scenes they were faced with on Mr Hargreaves' 5ha of land where he lives in an old truck.
The society has said charges under the Animal Cruelty Act are likely.
Mr Hargreaves, who kept at least 40 dogs in a large steel cage and old car wrecks, was still in shock yesterday, after the incident on Monday.
"If you had your family shot, how would you feel?" he asked.
"Even though they were dogs, they were my family. Life goes on but it's not the same."
He is keeping about eight surviving puppies, at his mechanical workshop in Wellsford.
Mr Mendoza did not wish to speak to the media yesterday.
A friend at his home, Maree, said he was preparing a statement, with his lawyer, to explain his side of the story.
However, the statement had not arrived late last night.
She said he had disconnected his phone because of malicious calls from the public.
Mr Mendoza and his wife run Home and Garden Wellsford, which advertises pet care.
Mr Hargreaves questioned his choice of occupation.
"He's supposedly an animal-lover.
He runs the local pet shop.
Where is the logic?"SPCA animal investigator Sascha Keltie, who inspected Mr Hargreaves' property the day after the deaths, said she was "confronted by a scene not unlike a massacre".
"I was in shock at first but I knew I was there to do a job. I had to get past the emotions," she said.
"It's not until I get home at night that it comes back to haunt me."
Mr Hargreaves has said he found one of his dogs attacking a sheep a day earlier.
He destroyed the dog and another with similar colouring.
Rodney District Council spokesman David Anderson said the only complaint the council had received about a dog belonging to Mr Hargreaves was in 2006.
None of the dogs was unregistered but the council would wait for the result of the SPCA and police investigations before considering fining Mr Hargreaves, he said.
SPCA executive director Bob Kerridge said charges "will definitely be considered" and the police are also considering firearms charges.
