Are there any hints toward [SPOILER]’s identity?

Are there any hints towards Charlie/Die Hardman’s identity before the end of the game? He breaks the fourth wall and says that some might have already figured out the DHV Magellan’s double-meaning yet I didn’t pick up on it. I just happened to choose Die Hardman as the voice of Charlie.

I’ve just learned that you can see him while taking a photo of the crew and that leads me to believe it was meant to be obvious.