The carcasses were found in the bags neatly tied around the branches of the tree.
It was city sanitation workers performing their annual cleanup who discovered the bags.
"It's something very odd," Ernest Lungaro, director of the SPCA of Westchester's Humane Law Enforcement Division, told the Journal News. "It's a lot of cats to be disposed of in a year."
Each bag had a cat inside. The carcasses were in the stage of decomposition. Most of the cats seemed to have been dead before being put into the bags, Lungaro told the Journal News.
The police refused to comment on the incident. It was too early to say whether someone killed the cats or was just disposing of their bodies, they said.
There was no evidence the animals were used in any rituals, Lt. Patrick McCormack told the Journal News.