Thanks again. I am planning to go to the police station and file a complaint. I will ask for a complaint form and likely send it by mail, in writing, with a some strategic carbon copies. I plan to mention "harassment, malicious threats, and violation of 1st amendment rights" with regard to being stopped, detained, being told to delete the images, and that I would be on a terrorist watch list. Even though the officers were "polite", the threat was serious and of a broadly and materially damaging nature, if the threat is followed through with (and even if it's not followed through with, considering I'm not sure if I even have the right or ability to know whether they follow through with the threat--I'm just left here wondering if a lifetime of being red-flagged and denied my rights is to follow this incident).
From what I understand I basically have no recourse against the Feds if I end up on the list, other than asking for a review of my status, which could result in a dead end. I wonder if I have any recourse against the local police officials for landing me on there in the first place. I imagine there is little precedence at this point.
I am going to ask for the officers names, and for a copy of the police procedures manual so I can review it for specific violations to reference.
I am also considering obtaining a permit to protest or demonstrate on the public sidewalk where the incident occurred. I figure this will serve the purpose of proactively allowing my presence and reduce the chance I am arrested or harassed by company officials when I revisit the scene (at least I'll have a piece of paper). It will also let them know that I am serious about my rights and serve as a public demonstration and protest of this incident.
I wonder if anything I mention raises any red flags, or prompts any commentary from you. Thank you for your assistance so far.