On Friday, officers were still investigating the scene.

Lt. Patrick McCormack of the Yonkers Police Department said that there were no suspects and that the motive remained unknown. Killing a cat in a “depraved and sadistic manner” is a felony in New York, punishable with a fine of as much as $5,000 and up to five years in prison.

Image Plastic bags containing the remains of about 25 cats were found hanging from a tree in Yonkers on Thursday. Credit... S.P.C.A. of Westchester's Humane Law Enforcement Division, via Associated Press

Because the crime scene was so strange, Lieutenant McCormack said, concerned residents had asked if there was any ritualistic element to the murders. Other than the care taken to hang the remains, he said, the killings did not appear to be ritualistic.

It remained unclear if the cats were domesticated or feral, the authorities said, but there were no recent reports called in about missing pet cats, officials said.

The authorities are doing forensic tests on the remains and other items found at the scene, and are canvassing the surrounding neighborhoods.

There is a large feral cat population in Westchester County, the S.P.C.A. said, and a colony of cats is known to populate the area around where the remains were found, a spot that is a half-mile east of the Yonkers train station.

Ora Ortiz, 43, said that she and an older neighbor feed some 30 stray cats in the area every day.

Ms. Ortiz said she had recently noticed something strange.

“There was a smell on this block for a while,” she said. “We were thinking it was trash.”

She could not have imagined someone was killing the cats she cared for so deeply.