Cooper inclines his head. “That would be helpful, until we’ve worked out whether he’s saying anything worth hearing.”

Westfall waves his cigarette. “Got it. Continue.”

“Um,” Emma says.

Neilsen smiles. “He means, please go ahead with your theory.”

“Okay.” She glances at Bell for support, receives a solemn nod. “Gutmunsson talked about how he thinks the killer is operating. His process. He said the blood is the most critical part of the killer’s ritual, and he thinks the killer is drawing blood from the victims, to check that he’s got suitable donors.”

“Like, he’s testing their blood type?”

“Yes? I think.”

Neilsen exchanges glances with Westfall. “Well, he can’t be testing blood type. ABO testing involves mixing blood samples with antibodies in a lab.”

“He could be, uh, tasting the blood as part of his ritual. Ingesting it.”

“Okay.” Neilsen is not as grossed out by this as Bell, which is disturbingly suggestive of the idea that he’s seen such things before.

“So I was hoping we could check the bodies for needle marks. To confirm whether Gutmunsson’s giving us anything solid.”

“Well, the bodies are in Harrisburg, but I’ve got comprehensive autopsy pictures from the most recent victims. Hold on.” Neilsen turns toward his desk, hunts through files. His brown hair is very fine and sticks up a little at the back from what Emma assumes is static electricity. He finds the file he wants, turns back.

He hesitates before opening the file. “These are… a little intense.”

She’s seen the crime scene photos and the ID shots, but these photos were not part of the file Cooper gave them. They are, indeed, intense. But the intensity of the images is in the way the postmortem process gives the viewer a clinical distance from the subjects, separating them into scaled body parts—a head, eyes closed; a torso; a hand; a length of leg. Emma finds this detached sundering vaguely offensive. She doesn’t want to think of the victims as body parts on a white background. She wants to keep thinking of them as people. But she supposes this is easier for the pathologists, to maintain scientific objectivity.

Bell steps closer from where he’s been taking up wall space near Cooper. Emma angles so he can see the photos in Neilsen’s hands from over her shoulder.

“Are we assuming the marks might be at the juncture of the elbow?” Neilsen sorts the images and pulls out the relevant glossies. “I mean, he could be taking the blood from anywhere.”

“That’s true,” Emma says. “But I thought the ligature abrasions might provide cover.”

“Doesn’t sound unlikely.” Neilsen displays a shot of a mottled arm. It’s clearly not from Lamar Davis, because the unmottled skin is pale, but aside from that detail Emma can’t tell whose arm it might be. “There’s some pallor from the exsanguination, but you can see how the abrasions stand out.”

Emma takes the photo and holds it close, then farther away. “Did they happen when the subjects were struggling, at the end?”