By the time police officers spilled into the room Friday afternoon he was already motionless, covered with blood from several wounds throughout his body and major injury to his head, according to a source close to the investigation who spoke on the condition of anonymity.

The room was "torn up," he said. "It looked like he put up a hell of a fight."

Authorities were still trying to determine Saturday what might have set off the attack while Faibish was home alone with Rex and Ella, 80-pound pets who had lived with the family since they were puppies.

Ella was shot to death by a police officer when the dog prevented him from entering the home, located a block away from Golden Gate Park. Rex was captured inside and taken to a shelter.

Dr. Carl Friedman, director of San Francisco Animal Care and Control, said Rex was being held isolated from other dogs.

"He did seem to have blood on him," Friedman said. "He didn't seem injured in any way. He's a pretty big guy. He (wasn't) very aggressive in the vehicle."

He said at least one of the dogs had been in protective custody at the animal shelter about a year ago.

"I don't know exactly why," he said. "It didn't have anything to do with showing signs of aggression."

Police were called to the scene by a neighbor after Faibish's mother, Maureen, discovered her son, and began screaming: "Help me! Help me!"

"Her face and arms were covered with blood," said neighbor Art Austin.

It wasn't immediately clear if both dogs were involved in the attack.

While Austin described the dogs as "sweethearts," not everyone remembered them as particularly friendly.

Asked about the dogs' behavior, 13-year-old neighbor Aaron Vinnick said: "Sometimes nice, sometimes mean."

Michelle O'Leary, who lives around the corner from the victim's home, said that the dogs appeared to be treated well by the boy and his family.

Not long ago, neighbors said, the victim and his brother found a patch of wet cement where the sidewalk was being repaired and scrawled the words "Rex SF."

"It was obvious he loved those dogs," O'Leary said.

Veterinarian Robert Arrick, who had treated the pit bulls at Park Animal Hospital, said he and his staff "never had a bad experience with them."

He said the boy's father, Steve Faibish, "walked (the dogs) up and down Ninth Avenue, in and out of stores -- there was never any problem.

Nicholas was a sixth grader at Roosevelt Middle School in San Francisco. His family, including a younger brother and sister, was going to move soon to Oregon, according to neighbors and teachers.

San Francisco has seen at least one other fatal dog mauling in recent years, the death of Diane Whipple in 2001. She was killed by two 100-pound-plus Presa Canarios in the hallway outside her Pacific Heights apartment.

Last Updated: Jun 4, 2005