Irene Collins, 73, was attacked by the canine as it searched her house in Middlesbrough for a suspected drug dealer in July 2014.
The dog, called Dano, then returned to bite Mrs Collins for a second time after it had been dragged off her by its handler, as the pensioner screamed “why has this happened to me?”.
A jury at the inquest at Teesside Magistrates’ Court heard Mrs Collins, who had lung cancer and chronic obstructive pulmonary disease, died four days after being bitten on the arms and legs by the dog.
On arriving at her home, her son Eric told a police officer that the incident “would finish her off”.
A Home Office pathologist initially reported that she had died of her injuries, despite her other medical issues.
PC Mark Baines and his police dog were searching for a male suspect after a car with heroin and £100,000 in cash had been stopped and he had fled.
Sergeant Neil Yates explained the situation to Mrs Collins, who agreed for her Penrith Road property to be searched. However, she was not aware that a dog would be needed.
After searching the garden with its police handler, the dog managed to get into the pensioner’s house, the inquest was told.
Sgt Yates was not in the house, and heard by radio that the dog had attacked the homeowner.
On entering the property, he saw Mrs Collins lying on the floor, with blood coming from her head. The dog was seen biting her forearm while PC Baines was yelling for it to “leave” and pulling it away by its collar.
Despite dragging the dog away into the hallway, it managed to pull free and attacked Mrs Collins a second time, clamping down on her leg, as Sgt Yates went to treat her.
Pc Baines managed to pull it off Mrs Collins for a second time.
Sgt Yates told the inquest that Mrs Collins was “screaming, upset, crying, saying ‘why has this happened to me?'”
Mrs Collins was given first aid and rushed by ambulance to James Cook University Hospital, where she passed away four days later.
Matthew Donkin, a lawyer for her family, asked if Sgt Yates, who was carrying a gun, had considered shooting the dog.
The coroner said the inquest would explore how the dog got into Mrs Collins’ house, its training and previous record.
PC Andrew Jobling, who was a plain clothes officer at the time, said that PC Baines had yelled he was going to bring the dog in for the search.
The inquest continues.