Let's say you have a plan. The goal of this plan is not relevant; maybe it's to colonize Mars, maybe it's to ensure the Detroit Lions win the Super Bowl. Part of this plan, though, involves poisoning a number of people. Not a large number of people, just a few. This is done covertly, and even if it is discovered that these people have been poisoned, the cause will be attributed to asbestos or unwashed spinach or something.
Would you make a list of these people? Would you leave this list in a place where anyone, at all, could find it? Would there be any possible reason to have a paper trail of this particular deed?