The case follows two others in less than two weeks.
"This is an extremely troubling trend," said Marc Peralta, chief operating officer of the Pennsylvania SPCA.
On Sunday, a man who barricaded himself inside a South Philadelphia rowhouse reportedly killed a small cat, set it on fire, and hung it on a fence on the side of his house. The man, who lived on the 1800 block of Dickinson Street, later surrendered to police.
Last week, a young pit bull named Chloe died of severe burns after being set on fire near the 700 block of Gray Street in East Germantown. Investigators have several leads, Marano said.
PSPCA officials said they did not know whether the two pit bull incidents were related.
The PSPCA is offering a $1,000 reward for information leading to the arrest and conviction of whoever set fire to Chloe.
People for the Ethical Treatment of Animals has put up another $1,000.
"We see a lot of cases of animal abuse in the city," Marano said, "but setting an animal on fire and leaving it to die is just heinous. We need the community to stand with us and not tolerate these kind of acts."
The PSPCA is planning a rally, "Justice for Chloe," to bring attention to extreme animal cruelty in the city. The rally will begin at 7 p.m. Thursday at the Pennsylvania SPCA headquarters, 350 E. Erie Ave.
"We don't know what causes people to do this," Marano said. "We can't even get into the mind of someone who would do this. But one thing's certain: We can't let anyone get away with these acts."
Authorities ask that anyone with information call the Pennsylvania SPCA's Anti-Cruelty Hotline at 866-601-7722.
Donations to the reward fund may be made by visiting http://pspca.org/support-us/donate/ or by calling 215-426-6304, Ext. 272.
Contact Sam Wood at 215-854-2796 or firstname.lastname@example.org, or follow
on Twitter @inqwriter.