Six puppies were killed, apparently by fireworks placed in their mouths, shortly after teenage boys were seen carrying Roman candles (search) in a north Tulsa neighborhood.

Animal control officers said they were following leads Tuesday but had no suspects in Sunday night's attacks, during which one person told police they heard a puppy yelp.

An older dog, a 4½-month-old black Labrador (search) mix, suffered burns on her muzzle and hindquarters from apparently being used as a moving target for fireworks.

The Tulsa Society for the Prevention of Cruelty to Animals (search) was caring for the injured dog and for the puppies' mother, a 1½-year-old black-and-tan heeler mix that was not harmed.

The injured dog had begun to eat and was expected to survive, said Laurie Mayes, executive director of the Tulsa SPCA.

The SPCA believes the puppies died from fireworks that exploded in their mouths.

A woman, Tonya Curry, 27, found all the dogs Monday among the remains of fireworks inside a vacant house and took the two survivors to the SPCA. When an animal control officer arrived later, the dead puppies were gone.

"Somebody probably went to clean up their mess so they wouldn't get in trouble," Officer Charity Curtis said.

The SPCA has raised about $1,000 and other organizations were undertaking similar efforts to reward people who provide information leading to the arrest and conviction of those responsible, officials said.