“And that’s all we’re capable of?”

“We? You and I are not the same as them, Dr. Grissom. We see the patterns their behavior always defaults to. We see how they react when offered sex or drugs or food. Have I not demonstrated this? Have my subjects not reacted with utter predictability at every stimulus?”

Grissom studied the man for a second before replying. “No, they haven’t. We found your greenhouse because of trace left behind on one of your workers’ belongings-possessions guarded for two months by people who owned less than him, people who didn’t even know his last name. Insects don’t do that.”

The Bug Killer stared at him. His pupils were tiny. “Do you know why I chose the initials LW? I wondered if you’d figure it out. If anyone could, it would be you-Soames is an idiot and Vanderhoff’s far more impressed with himself than he should be.”

“I didn’t-not until you killed the real Quadros. It stands for lacewing, doesn’t it?”

The killer smiled. He seemed to be having trouble breathing. “Yes. I remember how impressed I was as a child when I learned that some ants actually keep livestock-herds of aphids that they milk for honeydew. But not all aphids are cows, not at all. Some are sheep.”

“The woolly aphid.”

“Yes! It grows a waxy white coat of protective fibers…” He stroked his chin, seemed surprised to feel it bare. “But that adaptation pales beside the ingenuity shown by lacewing larvae. They will pick up discarded tufts of fiber and disguise themselves with it, literally becoming wolves in sheep’s clothing in order to slip past the ants guarding the aphid flock and prey upon their charges…”

He trailed off, his eyes unfocusing. He began to shake, spittle flying from his mouth as he collapsed to the floor.

“So this is the guy who sicced a spider on me?” asked Robbins. “Can’t say I’m sorry he’s dead.”

Grissom stared down at the body on the autopsy table. “We still haven’t been able to identify him. His prints aren’t in the system, and he wasn’t carrying any ID.”

“He just collapsed in front of you?”

“He presented a number of symptoms first-shaking hands, difficulty with his vision and breathing, profuse sweating. He went into convulsions, then vomited and became incontinent.”

Robbins frowned. “Those don’t sound like the symptoms of homobatrachotoxin poisoning.”

“No, they don’t.”

“Well, the tox screen will be back soon. In the meantime, let’s see what we can find out otherwise.” He picked up a scalpel and began to cut.

Grissom sighed and took off his glasses. He put them down on top of the postmortem report, which he’d read and reread a dozen times.

HBTX fatalities were usually caused by cardiac arrest, the poison paralyzing the heart. LW, however, had died as a result of respiratory failure. The tox screen told Grissom why: while LW had been poisoned, he hadn’t been killed by HBTX. He’d been killed by an organophosphate-specifically, parathion.

An insecticide.

Grissom reached for the phone.

Nathan Vanderhoff regarded Grissom quizzically from across the table. “I’m not really sure why I’m here, Gil.”

“I need to ask you a few questions, Nathan. It won’t take long.”

“I hope not. My flight’s this evening.”

“Yes, I know.” Grissom consulted the notes he had in his hand. “You and Quadros corresponded, correct?”

“Yes, of course. Only on a professiona l basis, though.”

“What about Jake Soames?”

“I hardly know the man.”

“But you’ve spent some time with him in Vegas?”

“Well, yes. He seems to thrive on the party atmosphere, though I’m beginning to find it a bit wearing. Perhaps he is, as well; the last time I saw him he seemed somewhat exhausted.”

“Did you ever notice Jake and Quadros together?”

Vanderhoff frowned. “I saw very little of either of them at the conference, but all four of us-including Charong-sat down together after our visit to the lab. Charong left first and I followed about twenty minutes later; I don’t know how long Jake and Roberto stayed after that.”

Grissom nodded. “Did Jake ever say anything to you about Quadros?”

“What do you mean?”

“Anything about him personally.”

Vanderhoff thought about it. “There was one thing that was a little strange,” he admitted. “The last time I talked to Jake, he referred to an ongoing project. From the way he talked, it sounded as if he and Quadros were working on it together-but when I asked him about it, he just laughed and said I’d misunderstood.”

“I see,” said Grissom.

Jake Soames met Grissom’s gaze without flinching. He seemed just as relaxed in an interview room as he did on a bar stool, the kind of easy acceptance of his surroundings that Grissom had never mastered.

“We caught the Bug Killer,” said Grissom.

Jake smiled. “Is that right? Congratulations all around. Too bad Nevada doesn’t use the electric chair-serve the bastard right to meet his end in a zapper, wouldn’t it?”

“He’s already dead, Jake. Poisoned by an organophosphate insecticide-not as flashy as being electrocuted, but just as ironic.”

“Parathion.”

Grissom studied Jake’s face. The smile had faded, leaving only a look of weary admission.

“You killed him,” said Grissom. It wasn’t a question; Grissom had known before he called Jake in.

“I won’t deny it. I snuck into his hotel room, the one he was staying in after he killed the real Quadros, and put it in a water bottle.”

Grissom wasn’t surprised. Nick and Riley were executing a search warrant on Soames’s hotel room as they spoke, looking for the parathion. Grissom had no doubt they’d find it, too.

“How did you know?” asked Grissom. “He had everyone else fooled.”

“I did some investigating on my own, Gilly. I we nt out drinking with the man.” He paused, then leaned forward with his elbows on the table. “You know, there’s some things you just can’t quantify, mate. Human nature’s one of them. Charong’s a pervert and Vanderhoff can be an arrogant prick, but neither of them’s a killer. Quadros-well, the psycho dressed up as him-was different. Get a few drinks in him and you could see that under all that bluster was nothing but contempt-contempt for the whole human race. If it was any of us, it was him.”

“So you decided to kill him?” Grissom shook his head. “That’s…”

“Cold? Inhuman?”

“I was going to say impetuous.”

“Ha!” Jake grinned. “That’s what I love about you, Grissom-I’ll bet you have a heart tattooed on your bum with science on the banner. But give old Jake credit for a little intelligence; I didn’t act without testing my hypothesis first.”

“You had proof he was the killer? Why didn’t you come to me?”

“Because the way I got it might have run into a few difficulties in court. It was enough to convince me, but a jury is another matter.”

“Would it be enough to convince me?”

“Judge for yourself.”

After they had taken Jake Soames away to be formally charged with the murder of the m an known as LW, Grissom joined his colleagues in the break room. They had all finished eating but hadn’t gotten up to leave yet; they were waiting for their boss.

Grissom sat down at the head of the table.

“Well?” asked Catherine.

“Braconid wasps,” said Grissom.

“Sorry?” said Greg.

“It’s how Jake Soames determined LW’s guilt.”

Nick leaned forward. “How?”

“Soames suspected that Quadros was the Bug Killer. He’d been working with braconid wasps in his own research and decided to see how effective they were. He surreptitiously sprayed one of the training chemicals on Quadros, then waited to see if there was another attack.”