This guy has done years of research, going through decades of local news, to find mention of Halloween candy incidents. While there is always room for error, suspicious deaths are generally reported at the local level, and the available data support the findings that nobody is out there poisoning children on Halloween.
They die by violence, by accident, by misadventure. Not by eating a piece of candy with a slightly defective wrapper.
I'm sorry. That's hateful. I don't understand why people take so much enjoyment in manipulating and lying to children.