Who abandoned this dying dog in the rain outside the Calgary Humane Society?

The Calgary Humane Society is looking for the owner of a dog left tethered outside of their building last week that was so “gravely ill” they said it had to be euthanized.

The elderly male Shih Tzu-type dog was found tied to a post on the morning of Thursday, June 15.

Surveillance footage shows the dog was abandoned at around 10 p.m. the night before.

The humane society said the footage wasn’t “sufficient enough” for them to identify the person who left the dog.

“There might have been an element of grace if they came in during operational hours and surrendered this animal properly, but this dog was in such poor neglect with a condition that had been for months,” Calgary Humane Society spokesperson Brad Nichols said. “Considering the mitigation of the offence…I have a hard time giving that grace.”

The dog was suffering from end-stage renal failure and had a large open mass on his hind end.

After abandoning him outside the humane society, the dog was forced to spend all night out in the rain.

On Thursday, the humane society issued a public plea for help as they seek the owner.

“This was a truly cowardly act,” Nichols said in a news release.

“To abandon an animal in inclement weather rather than fulfil his/her legally obligatory animal care duties is an act that will not be tolerated in Calgary.”

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The dog was in such distress when he was located that the humane society said they were forced to euthanize him.

“This animal was clearly badly matted, which is causing at best discomfort, at worst pain,” Nichols said. “And if there were medical concerns overtly obvious…any reasonable person would have realized the dog needed medical care.”

“We hope public tips will point us in the right direction so we can hold the offender accountable.”

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Anyone with information on the identity of this dog or his owner’s whereabouts is asked to call the Calgary Humane Society at 403-205-4455 or contact them through their website.

WATCH: The hunt is on for owner of abandoned dog that had to be euthanized in Calgary – Jill Croteau reports.

1:48 Hunt is on for owner of abandoned dog that had to be euthanized in Calgary

With files from Jill Croteau