“What’s up? What you got?”

“This young lady is postulating a theory, and we’re checking it out. Folks, this is Carlos Dixon, Comparison Analysis and Trace.”

“Hey, Carlos,” Cooper says. “How was court?”

“Great.” Dixon grins, wolfish. “We finally nailed Gower.”

“Good to hear.”

Westfall reclaims Dixon’s attention. “Carlos, you ever see someone debride tissue to conceal needle marks?”

“Sure. I trained in New York, I’ve seen everything. I’ve seen cigarette burns over needle marks. Tattoos, lacerations. One girl, her boyfriend said it was a dog bite.”

“This is abrasions at the ligature site,” Neilsen explains. “It’s Pennsylvania.”

“Ah, okay. Well, I’m not gonna say it’s outside the realm of possibility. You got the photos?”

“Yeah, you want both victims?”

“Can’t hurt.” Dixon finds himself a chair. He scans the visitors, smiles at Emma, then nods at Bell. “Hey.”

“Hey,” Bell replies.

Cooper thinks of something. “Glenn, have you got the matching shots from all four bodies?”

“Yup,” Neilsen says. “Lemme dig ’em out.”

Nielsen searches through his photo file again. The room is almost at capacity. Bell finds himself a chair near the wall. Emma, trying to take her mind off the pall of Westfall’s cigarette smoke, watches Carlos Dixon as he examines the photos.

“This would be easier if you had an internal ME, huh?” she offers.

Dixon nods. “Yeah, but then the case comes to court and the defense attorney nails the ME to the wall for cognitive bias.” He smiles. “It’s okay for us, we’re just lab grunts. But the coroner has to be impartial. So we have this curious little division of church and state.”

“I didn’t think about that.”

“Of course it could also just be because this is the FBI, and you know how government institutions love bureaucracy.” He grins at Cooper before turning to Bell. “This is pretty advanced work for a new LEO. You been doing this kind of thing awhile?”

Bell shakes his head. “Less than two weeks. And I don’t have my stripes yet, I’m still in training.”

“Yeah, I thought you seemed a little young to be this heavy.”

“It’s more hard-core than school, I’ll say that much,” Bell admits.

“Welcome to the real world, my friend.” Dixon turns to Neilsen. “Pass me the glass?”

Neilsen hands over the large, square-framed magnifying glass on his desk. Dixon spends a little time poring over the shots, then encourages Neilsen to move aside so he can spread the photos out. He turns on the desk lamp. Suddenly there they are, lit in stark relief: eight arms from four victims, all in various shades of gray. The insides of the elbow joints are scored with horizontal red lines, purple bruises, raw areas that bear a strong resemblance to ground beef.

“Hard to distinguish anything from the abrasions,” Westfall remarks.

“True. But look at the pattern.”

“What pattern?” Westfall cocks his head.

Dixon indicates the photos on the desk. “Left arms are more abraded than right arms.”

“What?”

There’s a bit of crowding around the desk—Neilsen pushes his chair aside and stands up. Dixon uses the handle of the magnifying glass as a pointer. “Left arm, right arm. That’s Ramirez. And here’s Barnes—left arm, right arm. You can see the tram-track bruising from the ligatures and some deep abrasions, but you’d expect the depth and severity to be consistent across both arms, right? Not here.”