Depends on who or what they turn out to be. Contact help if I can, or if it's a confrontation, do everything I can to stop them.

["Stop them" is a very vague way to put it, and intentionally so. Shun can't guarantee he wouldn't be trying to kill them if the situation came to it and he had nobody in line who was planning to dole out any justice otherwise.]

They're covering their tracks well enough that I doubt I'll run into them by chance, or know if I did. [There's definitely some people who'd be more worthy of suspicion than others, but the suspect pool is still too big.]