I looked at the flyer again, and then back at Mark. Very strange---meeting someone who didn't see me as a weirdo. But could it be true? Could there be a club dedicated to black magic?
using "could have":
I looked down at the glass table, an onset of tears stinging my eyes. Could Tom's mother have been right? Could I have been the one responsible for his death?
"Could" is the past of "can", but a the same time it can be used to indicate possibility (in the present tense). So, should I use "could be" or "could have been"?