I think I've figured out how to spot Jack as a user in rooms...

[LeadSolver]

I do not want to draw attention to it quite yet. I need considerable evidence to build & don't want him to change his behavior. Interestingly, he also pushes the limits of rooms like a few of us. I am just perplexed as to why he likes to swim the Fenn ponds... and I can use this in a special way.......

[LeadSolver]

That user recently posted in a room very specific things (again) that I'm tracking in the faulty Chase ending, and some bit of voice in his posts about why it was necessary for Jack and Forrest to burn the solver. (These things tend to perk up my reading ears). It's funny, I never would've suspected this person of being Jack if his anger didn't one day turn to me & I didn't notice his style of argument and insult.