A dog owner who gave up her pet for re-homing after postal staff stopped delivering to her street was "devastated" to learn it was put down.
Royal Mail suspended deliveries to Cardigan Close, West Bromwich, because of concerns the Staffordshire bull terrier rottweiler-cross could attack.
So Ilona Welch gave her dog - called Shylow - to a council dog warden on the assumption it would be re-settled.
Sandwell Council said there was no alternative but to kill the dog.
Miss Welch, who said she only found out about the death after being contacted by the BBC, said: "If I had known that [they were going to kill her] I wouldn't have given her up.
"She was a perfectly good dog."
Miss Welch said both Sandwell Council and her landlord had told her she would not be able to keep the four-year-old dog, called Shylow.
"I had no choice," said the mother-of-four.
"They said I can't have a dog here that stops the post."
Royal Mail sent residents a letter last month saying it had taken the "exceptional step" to suspend deliveries due to an "unacceptable level of risk".
It meant families had to collect their post from a sorting office two miles away in Lyng Lane.
A Royal Mail spokesman said the dog had behaved aggressively towards its workers on more than one occasion.
"Following removal of the dog, it was deemed safe to reinstate deliveries," he said.
Councillor David Hosell, Sandwell Council's cabinet member for highways and environment, said the dog was removed with the owner's permission because of concerns about its temperament.
"The dog was confirmed to be aggressive and unfortunately there was no alternative but to put it to sleep," he said.
"We understand Royal Mail has now resumed deliveries to Cardigan Close, as have other delivery companies."