How many people did the Phantom of the Opera kill?
How many people were confirmed as killed by Erik explicitly, either through narration or explicit witness testimomy?
How many people were there whose deaths were attributed to Erik without evidence proving his innocence (or word of god doing so), like Joseph Buquet.
I am only interested in events around Opera House - the question's scope excludes his earlier life before he became the Opera Ghost. Also, Leroux's book only - I'm not interested in the musical or other derived works.