“I don’t mean that,” she answered. “COD was suffocation. He put her in there alive. Why? Is he a sadist or something?”

Rhyme answered, “No, the Dancer’s not a sadist. He can’t afford to be. His only urge is to complete the job, and he’s got enough willpower to keep his other lusts under control. Why’d he suffocate her when he could have used a knife or rope? . . . I’m not exactly sure but it could be good for us.”

“How’s that?”

“Maybe there was something about her that he hated and he wanted to kill her in the most unpleasant way he could.”

“Yeah, but why’s that good for us?” Sellitto asked.

“Because”—it was Sachs who answered—“it means maybe he’s losing his cool. He’s getting careless.”

“Exactly,” Rhyme called, proud of Sachs for making the connection. But she didn’t notice his smile of approval. Her eyes dipped closed momentarily and she shook her head, probably replaying the image of the dead woman’s horrified eyes. People thought criminalists were cold (how often had Rhyme’s wife leveled that charge at him?), but in fact the best ones had a heartbreaking empathy for the victims of the scenes they searched. Sachs was one of these.

“Sachs,” Rhyme whispered gently, “the print?”

She looked at him.

“You found a print, you said. We have to move fast.”

Sachs nodded. “It’s a partial.” She held up the plastic bag.

“Could it be hers?”

“No, I printed her. Took a while to find her hands. But the print definitely isn’t hers.”

“Mel,” Rhyme said.

The tech put the bit of packing tape in a SuperGlue frame and heated some glue. Immediately a tiny portion of the print became evident.

Cooper shook his head. “I don’t believe it,” he muttered.

“What?”

“He wiped the tape, the Dancer. He must’ve known he touched it without a glove on. There’s only a bit of one partial left.”

Like Rhyme, Cooper was a member of the International Association for Identification. They were experts at identifying people from fingerprints, DNA, and odontology—dental remains. But this particular print—like the one on the metal lip of the bomb—was beyond their power. If any experts could find and classify a print, it would be the two of them. But not this one.

“Shoot it and mount it,” Rhyme muttered. “Up on the wall.” They’d go through the motions because it was what you had to do in this business. But he was very frustrated. Sachs had nearly died for nothing.

Edmond Locard, the famous French criminalist, developed a principle named after him. He said that in every encounter between criminal and victim there is an exchange of evidence. It might be microscopic, but a transfer does take place. Yet it seemed to Rhyme that if anyone could disprove Locard’s Principle, it was the ghost they called the Coffin Dancer.

Sellitto, seeing the frustration on Rhyme’s face, said, “We’ve got the trap at the station house. If we’re lucky we’ll get him.”