Martin Bryant, Tasmania
From Wikipedia, but available in other sources.
> His motivation for the massacre remains a closely guarded secret, known only to his lawyer, who is bound not to reveal confidences without his client's consent. The lawyer later released a book outlining that Bryant was motivated largely by the media surrounding the then recent Dunblane massacre. From the moment he was captured he continually wanted to know how many people he had killed and seemed impressed by the number. "
Why do these whiny little ti tty babies get to become household words? Is publicity not a serious suspect in motivations? The national news media pump the names up to encourage another.