“Play. Touch. Love—that’s what motivates her. She doesn’t care about finding bodies—she wants to please me and she wants to play. At the CETC they use a little white towel rolled up and taped at both ends. They have a room there with a whole wall full of holes. A trainer stands behind the wall with the towel; inside one of the holes is a sample of cocaine or heroin. When the dog detects the scent, he walks up to the hole and the man sticks the towel out—that’s the reward. The dog could care less about finding drugs; all he wants is the towel. That’s all the dog ever does—he spends his whole life searching for that little white towel. Funny, isn’t it?” She looked up at Nick. “What’s your little white towel?”

“I’ll have to give that one some thought,” he said. “What’s yours?”

“Finding my father’s body,” she said. “Now what?”

“Dogs are too easily pleased,” Nick said. “If I were a dog, I’d renegotiate my contract. I’d tell my trainer, ‘Hey, you sniff out the drugs and I’ll hand you a towel—see how you like that.’”

She laughed a little.

“You’ll be okay, Alena. You just need a new towel, that’s all.”

“Like what?”

“Like finding the man who killed your father.”

“I’d like that,” she said. “I’d like that a lot.” She released the dog and snapped her fingers, and the dog immediately resumed her position in the bow.

Nick looked out across the lake; they had been working most of the day and they had a lot of water still to cover. He tried to think like the killer: Where would he dump the body? There didn’t seem to be a logical place. He tried to imagine the body underwater: the bacteria running amok in the gut, producing methane and carbon dioxide that bubbled toward the surface in tiny specks of gas along with putrescine and cadaverine and the other malodorous by-products of death.

It seemed incredible to Nick that a dog could detect the chemicals in such tiny concentrations—but so can insects, he thought. Blowflies and flesh flies constantly hover in the sky, testing the air for tiny clusters of scent molecules, then follow the scent to the source. On a warm, clear day a blowfly can find a body within minutes of death—sometimes within seconds. If a fly can find a body, why not a dog?

A fly can find a body.

Nick looked to his right again and waited; a few seconds later he saw another splash of water in the same place as before. “Over there,” he said, working the pedals and bringing the boat around.

“Where?”