At about 4 p.m. last Friday afternoon Diane Whipple (33) was opening the door to her apartment in an upmarket San Francisco neighbourhood when her neighbour's two dogs lunged down the hall and attacked her.
The combined weight of the dogs was 233lb. Ms Whipple, a former star athlete at the University of Pennsylvania, weighed just 110. Within five minutes of the attack she lay mortally wounded with deep lacerations to her neck, bleeding profusely.
"When she arrived . . . she was in full cardiac arrest," said Dr S. Marshall Isaacs, a San Francisco emergency room physician. "There were no signs of life."
The dogs were both leashed at the time of the attack, but when the 123lb male, Bane, bounded from the apartment, his owner, Marjorie Knoller (45), was unable to hold the dog back.
"My wife was covered with blood from the top of her head to her feet," said Robert Noel (54) of Ms Knoller. "Most of it was somebody else's."
Bane was destroyed on the night of the attack, and the female 112lb Hera, which may not have inflicted any of the lethal wounds, is being kept at the city's animal shelter pending an investigation.
The dogs were a mix of English mastiff and Canary Island cattle dog known as Presa Canarios, a breed known for its strength and viciousness and often trained for fighting. The purebred Canario was considered so dangerous that it was outlawed in Spain in the 1930s, a move that almost led to the breed's extinction.
The story has transfixed San Francisco since it broke, not just because of the obvious tragedy of an attractive, vital young woman being mauled to death in her own apartment building, but because of the remarkable revelations which have emerged as the case has unfolded.
The couple, Mr Noel and Ms Knoller, initially said the animals had been obtained from a family that had given up the idea of breeding them.
But San Francisco police now say they believe the dogs had secretly been owned by two Aryan Brotherhood gang members serving life sentences at California's Pelican Bay Prison, home to the state's most violent criminals.
Mr Noel and Ms Knoller represent those inmates, and in a bizarre twist the couple officially adopted one of them, Paul Schneider (38), on Monday.
And in the most bizarre turn of all, yesterday, in rambling letters to San Francisco prosecutors, the couple blamed Ms Whipple for inciting the attack, saying she repeatedly entered the hallway outside her apartment and struck Noel in the right eye, causing the male dog to attack. Police say the letters paint a picture dramatically different from Mr Noel's original account.
Also, the couple now accuse the victim, a lacrosse coach, of using steroids or a pheromone-based fragrance which drew the dogs to her.
"The story just keeps getting weirder and weirder," said Ronn Owens, host of Northern California's top-rated radio talk show. Mr Owens's show has been jammed with callers now fearful of dogs they see in public parks, many of which are left unleashed.
The District Attorney's office has not made a decision about whether criminal charges will be filed, but if the dogs are found to have been trained to attack, the couple face the possibility of a three- to five-year jail term.
Locals meanwhile are devastated by Ms Whipple's death; many feel guilty that they had not reported the dogs earlier. Bouquets of flowers have collected at the apartment building's front door, and neighbours like Cydnee Dubrof, who had described Bane as "Killer Dog" to her friends and had avoided it, wonders what could have been done to prevent the killing.
"None of us ever filed a complaint, and that's what makes me sick now," she said a couple of days after the incident.