Detects if someone's a killer

Karl Decker was the smallest of the men; he wasn't much taller than I was. He was slender, but his muscles were wiry and tight. He walked with a sort of easy confidence that made him look like he was used to being in charge.

His eyes were utterly dead.

“He's killed people,” I said. “And not just the usual beating that serves for initiations in the Empire. He enjoys hurting people, and it wouldn't bother him to murder everyone in the room if it profited him.”

He strutted over to the third chair, the one the other two had reserved in the middle. He let himself be handcuffed to the table, casually and seemingly without worry. He really wasn't, either, unlike the other two, who were posing with bluff and bravado.

***

Karl was the man to reach, but he'd be almost impossible to crack. He didn't just lack a conscience, he was a full blown psychopath. It was his trouble understanding fear that made him struggle to empathize with anyone else. It was impossible to empathize about an emotion you didn't understand.

***

Interrogation