"Are you serious?" he asks.
"I am. Do it."
"Fine. I didn't commit this crime. Furthermore, I had no damn part in it."
You watch him. Any proficient poker player learns to look for the tells of other players: the little traits in their speech or body language or playing habits that betray an attempt at obfuscation. You look for the same sort of thing now in Bonnin. You've had little time to observe him—but still, a liar might betray himself under pressure.
He holds your stare for a long time—very fixedly, very fervently. It starts to seem that he's really forcing himself to, in fact, forcing an attempt at verisimilitude.
Did he help steal MetaHuman's money? You can't be 100 percent sure. Based on gut feeling alone, however, you feel that yes, he did.