Panel 1: Oh, jeez. For a second there, I thought John was about to be run over! Well, at any rate, Howard fleeing the scene indicates that he knows his actions are not kosher. Now, I wonder what the "BG" on his license plate (yes, I know it's not a vanity plate) could stand for? Big Galoot?
Panel 2: Don't call the police? Why not? That's what should have been done without John even going outside. Just report a suspicious person, and you don't even have to say you know (or "think", in Liz's case) who it is. And they don't have to know it was you who called.
Panel 3: Yes. Let's not mince words: he's not hanging around so he can admire the Pattersons' landscaping.
Panel 4: Oh, why does she have that earnest look? How does she plan on handling it? Not by informing Lawrence, if it's true that Howard "keeps" asking her out and she hasn't told him yet. And that ship has sailed anyway; it's now out of Lawrence's province (if you'll pardon the expression).
Panel 5: Could not have said it better myself. And even Edgar looks apprehensive!