“It’s a webcam!” Karim said triumphantly. “Yes, that’s right. Brilliant.” Everyone leaned in to get a closer look. “It transmits footage wirelessly,” Karim continued, now talking more to Jack than to Archie. “It was in the room where we found them.”

Archie could feel the mood in the room blacken.

“Gretchen set that up so she could spy on me,” Susan said. “She held me in that room, and she monitored me with that thing.”

Karim was turning the webcam over in his hands, studying it.

“You’re tampering with evidence,” Archie pointed out.

Karim’s face registered no emotion. He had stopped listening to Archie. This was entirely for Jack. “He was setting up surveillance,” Karim explained to Jack. He handed Jack the webcam and then stood up fluidly and brushed the wrinkles from his slacks. “Sheridan is a cop,” he added. “He wasn’t down there chasing serial killers. He was down there installing surveillance as part of an ongoing investigation into your activities. We’re all aware that you’re being watched. We’re aware that they’re building a case. Obviously, Detective Sheridan is participating in that effort.”

Jack was frowning at Archie, his knuckles white around the webcam in his hand. Archie tried to look trustworthy but his exasperation was making it difficult.

“Are we all familiar with the principle of Occam’s razor?” Karim asked the room.

Razor Burn coughed.

Susan sighed. “When you have two competing theories that make exactly the same predictions, the simpler one is the better,” Susan said.

“That’s not helping us,” Archie said to Susan.

“What?” she said. “I took philosophy.”

Jack’s face reddened and he hurled the webcam hard against the wall. It hit a framed photograph of a boat and then scattered on the floor in pieces.

Everyone flinched except Karim.

“I don’t have my badge,” Archie said emphatically, “or my gun or my phone or a walkie-talkie.” He glanced at Susan. “I’m here with a civilian. Without backup. You don’t use those tunnels. Why would I want to monitor them?” He pointed at the remnants of the webcam. “That’s not mine.”

Jack turned to Cooper, and for a moment Archie thought Jack might draw his finger across his throat and Cooper would shoot Archie in the back of the head.

“If I were here as a cop,” Archie said, “I’d be asking you to explain the bloodstains in your basement.”

Jack looked back at Archie. Archie had, for the first time, his full attention. The room was quiet.

“They didn’t tell you?” Archie asked.