My Name Is Red question

This is a book that seems to have many narrators... until the end, when we find there is only one: Orhan, who is writing well after the events depicted. Shekure even apologizes that the narrative might be altered for the sake of a better story (I don't have the book handy for the quote but it is essentially that she might be portrayed as more beautiful then she really is, Shevket as more unpleasant, Black as more forgetful etc. because Orhan is looking to write the best story possible)

So the corpse doesn't reveal himself because it isn't truly him talking; it's Orhan narrator who wants the identity to remain secret.

Because it was a murder mystery

because the creation was more important than the artist. He was more concerned about finishing the book than saving his life. In fact that is the common theme throughout the book.