Well, was he a good guy with a gun, or a bad guy with a gun? Don't you think the distinction can get blurry sometimes?
Since my situation is only a Google search away and mostly public record, I'll briefly comment on it.
The gun I was arrested for possessing in DC was a North American Arms mini-revolver, and a grand total of 5 rounds of ammunition. It's single-action, requires manual recocking between each shot, and has to be disassembled to be reloaded. It's pretty much the smallest, lowest power, and least accurate production firearm available, and is only reliably effective at contact range. It's small enough that if it's in a pocket with a few dollars worth of change, its presence is not very noticeable. (The photo below is not mine, but shows the same model in the same configuration.)
If you're planning on going on a shooting rampage at a high-security facility guarded by Secret Service and a variety of other well-armed security personnel, it's pretty much the least appropriate choice, except for Nerf products. It's also worth noting that the standard of evidence required for filing a criminal charge is pretty low, but I was never charged with anything related to any conspiracy or plot to commit any violent act, or with attempting to commit any violent act. What I was convicted of was possession of a device (at my house, over 70 miles from where I worked) that was only "unlawful" because it had not been properly registered.
I'll let you all draw your own conclusions as to whether I was plotting "workplace violence".