Aaliyah still does not believe that Arthur is a vampire. Adrian has to admit that Aaliyah is actually right: Arthur is not a vampire. But something else is happening...
"So what's your theory?" Aaliyah asks in a sarcastic and slightly irritated expression, "Arthur Hawthorne, who is actually a vampire, invited his twin for brother for dinner and had him as his main dish?" Adrian lets out another mischievous smile: "And I was the tactless one? But yes, that was my idea. The twin probably used his knife to defend himself, but... a simple knife won't work". "That still seems unlikely", replies Aaliyah, out of field "besides, what would it have to do with the other murders?" Adrian keeps looking down at the corpses, thinking. "It'd be... complicated. Anyway, you're right. Ol' Artie's teeth are fine. Those that aren't missing, I mean. He was not a vampire". "Good, so now that you're done playing dentist, you may want to take a look at this..." is Aaliyah's reply, as she stares in shock at... something that is happening out of field.

Transcript

Aaliyah: So what's your theory? Arthur Hawthorne, who is actually a vampire, invited his twin for brother for dinner and had him as his main dish?

Adrian: And I was the tactless one? But yes, that was my idea. The twin probably used his knife to defend himself, but... a simple knife won't work.

Aaliyah: That still seems unlikely. Besides, what would it have to do with the other murders?

Adrian: It'd be... complicated. Anyway, you're right. Ol' Artie's teeth are fine. Those that aren't missing, I mean. He was not a vampire.

Aaliyah: Good, so now that you're done playing dentist, you may want to take a look at this...