[He gives a sheepish laugh and waves his hands as he backs up.]

Well maybe, maybe, I might have had a suspicion or two! I mean, most people operating in dark alleys at this time of night are... typically up to no good! But, um, uh, I'm not here to make any... potentially false accusations!

[Darkwing makes some quick glances around. This wouldn't be the first time he's accidentally barged in on someone who's actually innocent - but that's assuming this person really is innocent!]

If you did happen to be to no good, then I'd have to battle you! It's as simple as that.