Bunk points toward the fridge, then looks back at the window: "Motherfuck!" He takes back the photo of the window, noting what I think is glass dust on the sill. Offscreen, McNulty says, "Oh, fuck. OH fuck!" Bunk holds up his own gun, such that it's pointing at the window from the outside. McNulty approaches, pointing to his chest again, and at his hip with his other hand. Basically, if the shooter was outside, and Diedre had come close to the window, leaning over, to see who was there, then the forensic evidence all makes sense. So D'Angelo's story checks out. And Jay was right! There are a lot more "fuck"s as McNulty gets in close to the little lip of wall by the fridge where the bullet should have lodged. But then he looks at another photo -- one that shows Diedre with her butt pointing up at the camera, so that actress's parents must have been proud -- with a few drops of what look like milk around her wrist. Sure enough, when McNulty opens the fridge, he can see the spot in the door where the bullet must have struck. The hole has been filled with some kind of caulking, which McNulty starts to pick at. Bunk goes to the knapsack McNulty'd brought with him and produces a set of pliers, and with some effort, McNulty's able to pry out the repair material and pull out a slug. "Check this," he says, holding it up in the pliers. "Motherfucker." Bunk takes the pliers and gazes at the slug: "Fuck me." McNulty spreads his arms, imagining the shot coming in; he sort of hits the fridge door, and it bounces back against the bit of wall that's there and slams back, closed.