Looking for some helping understanding the end of the below (more in context, rather than literally what is said). I can see how it was translated but I am unsure what is correct. To provide some context, the protagonist has been cross-dressing (unwillingly) when his club were carrying out certain activities and he has acquired quite a fan base with very few people outside his club knowing this it is him. Now in return for allowing their club to keep their club room the chairman wants to have a personal photo session (個人撮影会).
The bold line was translated as "He probably knew from the beginning." (i.e. the chairman knew that it was him from the beginning) however I am not quite sure this is the correct translation of what was said. I would have expected this to be phrased differently if she was saying that e.g. a sentence using バレている, 気づいている etc. To me I interpreted it as a response to the previous comment. Could anyone help clarify the correct understanding?