They all said he was a nice dog.

But something inside Zeus snapped this morning.

The American bulldog who loved dog biscuits and backscratches went berserk and attacked an 11-year-old neighbor as the boy and his friend got ready for school in Port Richmond.

Thirteen-year-old Brad Bucher heard his brother screaming and sprinted to help. The scene outside his home on Mercer Street near Tioga seemed straight out of a horror movie: Shane struggled frantically on the sidewalk, Zeus' teeth sunk into his bloodied neck.

"I was trying to push him off, to unlock his jaw. But he was just attacking him," Brad said, four hours after the 8 a.m. mauling.

Neighbor Bill Reynolds had heard the horror unfolding outside too. The 46-year-old Reynolds grabbed his .357 Magnum, bolted toward the boy and dog and aimed carefully, blasting Zeus twice until the hulking dog loosened his grip on Shane. Brad flew off to call 9-1-1 and his dad, who was at work in Nicetown.

Shane, a fifth-grader at Bridesburg School, is in stable condition at St. Christopher Hospital for Children after undergoing surgery. The dog ripped part of his right ear off, bit his neck and chewed his side open, injuring his intestines, his grandfather Ralph Bucher said.

As a neighbor used bleach and a garden hose to remove the bloody path off the sidewalk, stoop and doorjamb, the dog's owner and other neighbors cussed out reporters and made obscene gestures at them. On the front door of one angry neighbor was a sign proclaiming: "Pets Welcome, Humans Must Be on Leash."

Other neighbors gathered to await news of Shane's recovery and speculate about what prompted Zeus' savagery.

"The dog's great; it's so friendly," said Melissa Pomroy, Reynolds' fiancee. "My dog loves that dog. It hurt him [Reynolds to shoot Zeus] because he liked that dog."

Det. Sean Walsh of East Detectives said investigators hadn't uncovered any past complaints about the dog. Still, today's attack seemed unprovoked, he added.

The boys were inside the yellow-brick rowhouse where Zeus lived when the dog attacked, Walsh said. Shane staggered outside, with the dog's jaws clamped onto his neck, then Brad and Reynolds came to his rescue.

"The kid's familiar and friendly with the dog," Walsh said. "The kids were just going about their general routine of getting ready for school."

Agents from the Pennsylvania Society for the Prevention of Cruelty to Animals removed the dog's carcass. It will be tested for rabies, as is routine in such attacks, said Jeff Moran, Philadelphia Health Department spokesman.

Paul Bucher stopped home just before lunchtime, with his son midway through a four-hour surgery, to retrieve items Shane requested.

"His cell phone and his Tech Decks [toy skateboards]," Paul Bucher said with a strained smile. "He thinks he's going to be the next Tony Hawk."