In this AP article:
http://story.news.ask.com//article/20070418/D8OJ5AHO0.html
there is the following quote regarding the suicide notes:
“He also expressed disappointment in his own religion, and made several references to Christianity, the official said.”
The way that sentence is written it implies that his religion is not Christianity, but it doesn’t say what it is. This is the first reference I have seen that indicates that Cho had a religion. Maybe the sentence is poorly written and meant to say that his religion was Christianity, but it leaves it ambiguous. It is a piece of the puzzle for those who would like to understand his thought processes.
You might want to consider that we do not know all the information. We are not forensic analysts, we do not study symbology or iconography.
And do not forget, “Ismail” is Hebrew for “Ishmael.” Ishmael was the son of Abraham, or “Ibrahim” before it was changed. In Islamic tradition, it was Ishmael who was supposed to be sacrificed by Abraham, not Isaac. I don’t get why everyone is talking about Abraham, or Ibrahim.