Update, Aug. 16:

Update, Aug. 15: A 32-year-old pregnant woman from Pacifica was attacked and killed by her family's pet pit bull Thursday, police said.

received a 911 call at approximately 12:15 p.m. about a possible dog mauling in the 500 block of Reina Del Mar Avenue. The first officer to arrive on the scene located the victim, Darla Napora, lying in the front room of her home, Pacifica Police Chief Jim Tasa said. "The victim had major trauma, was not breathing or responsive," Tasa said.

The first responders' efforts to revive the woman were not successful. The victim's husband, who had called the police and was at the scene when they arrived, told police that their 2-year-old male pit bull had attacked his wife after he left for work. He said the dog had been secured in their backyard before he left.

While paramedics and fire department personnel were tending to the victim, the dog escaped from the backyard and began approaching them in the front yard. Police officers shot the dog three times, killing it, Tasa said.

The victim has been released to the San Mateo County Coroner's Office and the dog's body was released to San Mateo County Animal Control.

There was a second dog, another pit bull, in the backyard. It and the deceased dog were taken to the Peninsula Humane Society for examination. An autopsy for the woman and a necropsy for the dog are scheduled to take place Friday.