"My dog... is biting my sister... Come on, hurry, please!" the frightened boy told a 911 operator on the call, a copy of which was obtained by NBC 4 New York.
It was unclear what led the 100-pound dog to attack the 15-year-old girl.
When a police officer arrived at the Starmond Avenue home at about 1:30 p.m., he found the girl covered in blood, being chased by the dog, which had blood around its mouth, police said.
When the officer intervened, the dog began to attack him, according to police. The officer fired two shots at the pit bull and took the girl outside to arriving patrol officers.
He re-entered the home with other officers, and they contained the dog in the laundry room. When an animal control officer attempted to capture the dog with a snare, the dog charged. In response, the first responding police officer fired another shot from his service gun, killing the dog.
There was "a lot of blood in the basement from the victim, and also from the dog," said Bob Boyle, of Clifton Animal Control. "It was not a pretty scene. We run across a lot of incidences like this with large-breed dogs."
Police said the boy was in shock when officers arrived.
The dog, which appeared to be 2 years old, was unlicensed and not neutered, and the family will be fined, animal-control officials said.
Investigators said the boy who called 911 had also previously been attacked by the dog.
"It was stated to us that when the dog was six months old, it bit the boy in the arm," said Boyle. "He was playing with the dog, and it attacked him."
The boy had a large scar on his forearm from the incident, police said.
Neighbors said they had not seen the dog misbehave. But Ginger Love installed a gate at her house as a precaution.
"I have a newborn, and the pit bull sometimes gets loose," said Love.
The 15-year-old girl sustained severe injuries to her arms, legs and abdomen, and was taken to St. Joseph's Medical Center in serious condition.
The family could not be reached Thursday.
(NBC New York - July 20, 2012)
