Cold and alone, Dusty the dog was dumped and left to give birth to her puppies in a wheelie bin.
Despite attempts by volunteers from Animals in Need Northwest to save her, the young dog was so badly injured and neglected that she died yesterday afternoon.
Council animal welfare officers had visited the dog over the weekend but did not deem it to be an emergency.
On Sunday afternoon, volunteers from the charity found her and her puppies dumped in the bin inside a shed at an abandoned Travellers site in Strabane and she was finally taken to safety.
Gareth Connor, founder of Animals in Need NW, said: "We'd heard there was a mother and pups there and she was very small so we initially thought she was the only one, but then there was a noise and we found the puppies.
"We think they were probably born on Sunday morning. She'd given birth in that wheelie bin. She'd been dumped there when she was pregnant. She was in a wild state. It was really awful."
Mr Connor added: "If she had been left one more night, they would have all died. The pups were freezing. It's December and the weather on Sunday night wasn't great. Thank goodness we found them when we did."
One of her six babies had already died in the bin and the others were left fighting for survival.
The dog, who they named Dusty because she was found in a dustbin, was also so seriously ill that she stopped producing milk and couldn't feed her babies.
Volunteers rushed her to the Drumahoe Veterinary Practice in Londonderry on Sunday night but she had horrific internal injuries and died yesterday afternoon.
Mr Connor added: "The vets were fantastic. She was kept in overnight and Declan the vet stayed with her all night, but with further investigations, they discovered she had fluid in her lungs and internal bleeding and she died.
"This is an extreme case. Karen, one of the girls who helped to rescue her, said this is one of the worst cases of neglect that she's come across and she's been volunteering for 16 years."
Dusty's five puppies are now being reared by hand in foster homes across Northern Ireland.
"They have to be hand fed so they'll stay with fosters until they are a bit stronger and then hopefully they'll find homes", Mr Connor added.
A spokesman for Derry City and Strabane District Council confirmed that an animal welfare officer responded to a call over the weekend of a dog in alleged distress in the Strabane area.
They said: "Following discussions with the PSNI who attended the site in question, the officer was satisfied that the animal was in no immediate danger."
Animals in Need NW is now asking for donations to help it care for the tiny puppies. Anyone who would like to help pay for their vet bills can call Drumahoe vets on 028 7131 1448. For more information visit https://www.facebook.com/Animals-in-need-NW-176947292643369/