It's simple. You could kill them off with different drugs, have them die in traffic accidents, drown while swimming at the ymca, fall down the stairs and break their necks. Accidents happen all the time. Even to hot people. And it's not like people you don't write names for will stop dying. Accidents every day. Millions of people die daily.
Oh and just to make it look even less suspicious, you could go to different towns to find victims or send your victims to live in other towns before they die