The popping sound of firecrackers is common around Ditman and Levick streets in Tacony, neighbors say.

But last night that sound came from a gun used to shoot a pit bull in the head.

It was the second pit bull that was found killed in a public area in two weeks.

About 10 p.m. last night, residents on Ditman heard a "pop, pop" but thought nothing of it until cops arrived in the back alley way about an hour later.

Police found a brown pit-bull mix laying in a puddle of its own blood, tied to a fence post with a gunshot wound on the side of its head.

One neighbor, who was watching TV, peered out the window into his back yard and saw the gruesome scene lit up by the flashing blue and red lights of a nearby police car.

"I couldn't see anything" at first, Carlos Rodriguez, 35, said. "It was so dark. But when police came, I saw the dog tied to my fence post."

Carlos and wife Ana were confused as to why the dog was tied to their fence in the first place, Ana said.

"There are plenty of other fences," Ana said. "They see we have a pool here, and they know our kids play in it every day, so why would they do it here?"

Police were still looking yesterday afternoon for the owner of the dog and who might have shot it, a police spokeswoman said.

"It's just weird," said David Cheatley, 30, who lives four houses down from Rodriguez's rowhouse. "We all have dogs here. Why did they have to do that right there where our kids could see?"

Dave Browning, 59, who lives between Rodriguez and Cheatley, said that in the last year his 9-year-old granddaughter has witnessed four deaths - three people hit by cars and now the dog.

"She and my wife were coming home from her dance-recital rehearsal," Browning said. "And when they pulled up, my granddaughter saw the dog laying in the street."

Browning's wife, Donna, then called police at 10:45 p.m., saying she saw a gunshot wound in the dog's head, police said.

"It's such a shame," Browning said. "When my granddaughter came in, she bent down and hugged our dog and said, 'Don't worry, I'll protect you.' "

The dog's body was picked up by the Pennsylvania Society for the Prevention of Cruelty to Animals.

On June 15, a pit bull was found dead hanging from playground equipment at an Olney rec center. The dog had been hanged by its leash at Barrett Recreation Center, at 8th Street and Duncannon Avenue.