A seventh mutilated cat was found Sunday morning in Washington state, marking the latest victim in a string of gruesome pet murders that police have attributed to a serial cat killer. The Washington Post reports that in each incident, the killer removed the cat’s spine and placed the body in a public area. Officials added that the deaths were too “clean” to be accidental, which suggested the presence of a serial killer. Examiners hope they will be able to recover DNA from the murdered cats’ claws to help identify the killer, who could face as much as five years in jail and a maximum fine of $10,000. Residents have been cautioned to keep their cats inside, and many are concerned that the killer could target humans, too. “This is not normal, and it’s very sick behavior,” one animal-welfare investigator told the Post.