DNA tests will be done to determine if the puppies are dogs, coyotes or some other domestic or wild animal, while necropsies will be conducted to learn how they died.
A woman walking her dog found the bodies Friday in woods near a park in Lower Macungie Township, outside Allentown, the Lehigh County Humane Society said. The bodies were in or near a bag that had been torn open, perhaps by an animal.
Unless a witness comes forward, it's usually difficult to make arrests in animal cruelty cases, authorities said. And that means the person's motive remains unclear.
"It could have been kids or some whacked-out person who found an abandoned litter of puppies or coyotes and just thought they'd have some fun," said Cary Moran, the county humane society's shelter manager. "That's what's so scary about not being able to (solve) these cases, and find out what happened, because you don't know who's out there. Because, unfortunately, animal abuse is a precursor to harming (people)."
The discovery came the same week another animal was found skinned, with its feet cut off and rope tied to one leg, about 20 miles away in Lynn Township. That involved a larger animal, perhaps one sought for its pelt, according to humane society Officer Christine Wiggins. Two pairs of thin latex gloves were found beside the animal and will be sent to a forensics lab.
If it proves to be a coyote, the case may amount to little more than a citation for improper disposal, since it's legal to hunt coyotes in Pennsylvania. But investigators thought legitimate hunters would have disposed of the body properly.
Wiggins believes the two cases might be related, given that the animals were skinned. The puppies appeared to be a few months old, weighing less than 10 pounds, according to Moran, who added that it's hard to know their age without knowing the breed.
An animal advocacy group has offered a reward for tips that lead to an arrest and conviction.
"Somebody purposely took time and precision and skinned animals, over and over. It's really disgustingly gruesome. I can't imagine what's going through somebody's head when this happens," said David Lee of the Lehigh Valley Pitbull Awareness Club.
Neighbors and friends are often reluctant to report animal cruelty, fearing retribution, animal welfare officials said. This has proven true even in notorious cases in which animals are set on fire, the Pennsylvania SPCA said.
"Someone usually knows but is afraid to come forward. Often there are multiple witnesses who maybe feel intimidated to not `snitch,"' said spokeswoman Wendy A. Marano. "These are disturbing cases -- not only are helpless animals suffering cruel fates, but it's unsettling to know that people capable of these kinds of depraved acts are members of our own communities."
Coyotes are now more common in Pennsylvania than black bear or bobcats, according to state game officials. The Pennsylvania Game Commission now allows them to be hunted and trapped to reduce their population. More than 43,000 coyotes were bagged in 2010, according to commission data.