Honolulu police have opened an animal cruelty case after bags of animal remains were found in a gully in Nana­kuli last weekend, police said Monday.

Hawaiian Humane Society investigators were on the scene Monday, examining the rotting carcasses and skeletal remains of dogs and other animals that were discovered Saturday off Lua­lua­­lei Naval Road.

Investigators found the remains of 11 animals and no signs of animal cruelty Monday.

But the person who made the discovery Saturday and returned to the area Sunday said she counted remains of more than 30 animals, many of them dogs, packed inside large yellow bags of dog food.

"I was in complete shock," said Emily Snyder, a student at Campbell High School in Ewa Beach. "It was disturbing and heartbreaking to see."

Volunteers with the nonprofit group K9 Kokua and Snyder’s mother, Shannon Rountree, an employee at Animal House Veterinary Center, helped scan the remains for microchip identification but found nothing.

The Humane Society of the United States is offering a $5,000 reward for information leading to the arrest and conviction of the person or persons responsible for leaving the carcasses.

"We’re just hoping someone saw something," said Inga Gibson, Hawaii director for the Humane Society of the United States. "Whoever did this didn’t want the remains to be found."

Gibson said she is urging a complete investigation that would include hiring a veterinary forensic investigator.