YONKERS, N.Y. -- An investigator says at least some of the 25 cats found in plastic bags hanging from trees in a New York City suburb were killed with blows to the head.

Ernest Lungaro of the Westchester County SPCA said Friday that tests on three cats revealed blunt trauma to the head.

He said a baseball bat, two shovels and a metal pipe were found near the scene in Yonkers. Some of the cats were just skeletons and some had been dead for only three days. A city cleanup crew found them Thursday.

Lungaro said there has been some tension in the neighborhood over feeding stations some residents set up for a large population of feral cats.

The SPCA and Yonkers police are investigating. Lungaro said it was too soon to say there's a suspect.