“Shark,” Rhyme said absently.

“The big shark. They get their first glimpse of it—it’s really big—and one of them says, ‘I think we’re going to need a bigger boat.’ That’s us.”

“Boat?”

“Jaws. The movie.”

“I never saw it,” Rhyme muttered.

# # #

The murder weapon was about the only easy part of the analysis: It was the victim’s car.

The killer had snuck up behind and hit her, probably with a piece of rock or cinderblock, hard enough to stun, but not kill, her. He’d then taped her eyes, mouth, feet and arms and dragged her behind the car. Then Unsub 26 had started the Prius and backed it onto her abdomen, leaving it there. The Toyota is front heavy, with the rear weight about 530 kilos, Rhyme had learned. Only one wheel was resting on the victim, which would have cut down some of the pressure, but the medical examiner said the internal damage was devastating. Still, it took her close to an hour to die—mostly from shock and bleeding.

But apart from the COD determination Rhyme and his team had made no other evidentiary discoveries. In fact, all they’d been able to do was catalog the evidence, everyone chipping in: Sachs, Cooper and Marko. Even Thom was helping.

Lon Sellitto arrived.

Oh, Lord no…

Rhyme had to laugh, though bitterly, seeing that the big detective was carrying yet another massive box of evidence collection bags.

“Not more?” asked a dismayed Mel Cooper; usually he was the epitome of detached calm.

“They found another exit route.” The big detective handed off the box to Marko. “But this should be the end of it.” Then he frowned as he looked around at the hundreds of collection and sample bags lining the walls throughout the first floor of the townhouse. “I don’t have any idea what the fuck’s going on here.”

But Lincoln Rhyme did.

“Oh, what’s going on, Lon, is our unsub’s smart. He’s brilliant.” Rhyme looked around. “I say ‘he,’ but remember, we keep open minds. It could be a she, too. Never make assumptions.”

“He, she or it,” Sellitto muttered. “I still don’t get it.”

The criminalist continued, “You know Locard’s Principle?”

“Sorta.”

“How about you, Marko?”

The young officer blinked and answered, as if reciting. A hundred years ago, he said, the famed French criminalist Edmond Locard developed a theory: In every crime there is an exchange of evidence between the perpetrator and the victim or the scene. The trace elements swapped may be extremely minuscule but they always exist and in most cases can lead to the perp if the investigator has the intelligence and resources to discover them.

“Close enough. Well, at the scene—” Rhyme’s hand rose unsteadily and he pointed at the pictures Sachs had shot of the victim’s body and that Cooper had printed out “—we know the unsub left something of himself. He had to. Locard’s Principle is never wrong. But, you see, he knew he’d leave something.”

Sachs said, “And rather than trying to clean up all traces of himself afterward, he did the opposite. He covered up many clues as to who he is, why he’s doing this, what he has planned next.”