Regarding the clues about Neb's murderer: the description ends with the phrase "What a loss." I don't see any other contenders for the clue. And in this context, the Lizardman bothers me. Both with the signature about the disappearance and with his overall dinosaur-like profile, as their demise was quite a loss.
Regarding Ara: he greedily gulped down the air. Isn't that an indication of the deceased's vice?