@GilliamYaeger
Initially you feel like the boy is telling the truth. After all, maybe he's just worried about his mother and angry that you all upset her so much? There's something in his voice, however, an undercurrent of wariness that seems at odds with such emotions that you just barely make out. You feel that perhaps he is hiding something.
@Dirtnap
You detect much the same as Gill, though you are a little less distracted by Kairi and focusing more on Ota. The boy is too on edge. You believe he might be hiding something, and you're fairly sure it's information about he knife.
@Rook
At first glance it seems like Ota is just being sullen and surly, which you've already taken to be his default personality. But as you observe him a bit more carefully, you see that his posture grew slightly tense when you asked him about the knife. You believe he might not be answering truthfully.
@EtchedSteel
You can tell from Ota's tone of his voice and his body language that he is lying like a goddamn rug. You get the impression that Ota has
definitely seen the knife after its disappearance and is trying as best he can to deflect. You, however, see through such meager efforts with ease.