Angela showing Dexter the heat sensor footage again

What was the point of that? she pulled out the footage and showed it to him like she was gonna have some proof Dexter was the other guy, but all she said was "He has the same build as you, and the same gun and scratches his chin like you" and? where's the proof its him?

Dexter even called her out for it "I'm average sized and everyone in town owns a gun like that, and i don't even know what you're talking about with the chin scratch thing" yeah i don't recall Dexter doing a chin scratch thing or maybe i'm forgetting.