Outrage is growing in the small North Canterburycommunity of Cust after a resident claimed her two dogs were poisoned by another local.
The incident left one dog dead and the second on life support.
After her family's two beloved dogs set out to chase rabbits on Friday evening, Brooke Wallis was called by a neighbour who said they could hear the pets "yelping" from a local property.
Driving to the property with her family, they whistled to the two small dogs to call them out.
They didn't rush back to their owners but Wallis could hear them howling, she said on Facebook.
"My husband decided to drive up to the culprits home to check, they didn't appear to be home," Wallis wrote.
"He found our dogs in a holding pen at their home, with their legs tightly bound with bailing twine upside down. My husband broke them free and rushed them home."
But one of the two, Bonno, was in a bad way - he couldn't walk or move properly.
The family sped to the vet, who prescribed anti-inflammatory medication for Bonno.
"We nursed Bonno all night in our bed, while he squealed in pain," she wrote.
"It was heartbreaking."
But as the family arrived home, Wallis said they found "the culprit" standing in their driveway, saying they were "looking for a dog."
The next morning, one of Wallis' children found one of the dogs eating balls of mince that looked to be sprinkled with powder and tablets.
"I ran outside to see and collected all the remaining evidence. In the mince, was a aluminium cut off from the medication with the letters "PHEN".
"I phoned the vet back immediately and they suspected it could be "Phenobarbitone" which is used to treats humans and animals with epilepsy. In high doses, it is fatal."
Within 30 minutes Clyde, who earlier appeared uninjured although traumatised by the previous night's ordeal, was disorientated and struggling to walk.
"I rushed both boys to the vet, they ran bloods and started treatment immediately," Wallis wrote.
"The blood tests confirmed Phenobarbitone overdose. They had consumed so much, that the tests were off the scale. Both boys were in critical condition and on life support."
That night, Clyde died from the overdose.
The family's other dog, Bonno, remains in critical condition. If he survives, he faces permanent liver damage.
"We are absolutely devastated," Willis wrote.
"Our daughters are 14 and 7, and they've spent their weekend sobbing and scared that someone could come to our home and hurt our family in this way."
Police received two reports in relation to animal welfare offences against dogs in Cust on May 1 and May 2, a police spokeswoman said.
"Inquiries are ongoing, however no arrests have been made or charges brought at this stage."
READ MORE:
• Pet owner heartbroken after dogs die from suspected antifreeze poisoning
• Vets urge dog owners to be wary of poison
• Leanne Norman: Rat bait poisoning common in dogs