Mikey did the same thing to his family as it turns out.
He was pretty happy about offing both of his parents. He had both of Terri's cats euthanized, not because there was anything wrong with them, but because there was something wrong with him. Jodi's mother died mysteriously in Mikey's home. Since he works for the sheriff, it may never be properly investigated. I wonder how many other deaths are connected to him.