What do the flowers mean that are in the priests bible in the movie Doubt?

I read somewhere that one "he's guilty" theory is that the flowers are tokens of the boys' that he had abused in the past. According to this opinion, it's not uncommon for those guilty of such a crime to keep reminders, tokens, or a tally of some sort to remind them of the other boys. I'm not sure I agree with this interpretation, but it's one opinoin.