Up to $5,000 was being offered for information leading to the arrest and conviction of the person or people responsible for leaving the bodies of a cat and six birds arranged in a circle in Echo Park.
The discovery a cat, a seagull, a crow and several pigeons was made Friday near Sunset Boulevard and Rosemont Avenue, officials said.
"The animals ... may have been the victims of a satanic or other ritualistic killing," said Stephanie Bell of People for the Ethical Treatment of Animals. "And PETA just received a report about a missing cat in the same neighborhood."
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The cat was in the middle, the birds left in what appeared to be a circle around the feline. PETA staffers noticed the animals as they walked by on their way to lunch.
PETA initially offered a $2,500 reward, but doubled it, in an announcement on Tuesday.
The case was being investigated by the U.S. Fish and Wildlife Service.
Anyone with information is asked to contact PETA directly at 757-622-7382, ext. 8037.
City News Service contributed to this report.