"Garret, if you don't want…" McCarthy started.

"Tell me again how I know I'll be safe," Garret said, still staring at the table.

"Okay, let's go over that," McCarthy said. "A state trooper is being assigned to you as a bodyguard. That person will be with you for at least six months, much longer if anyone you implicate in a crime is ultimately brought to trial. It's important you understand, though, as we've informed your mother and your lawyer: There are no guarantees. Nothing we can do will take away every bit of risk."

Garret pursed his lips, apparently pondering what he had just heard.

All I could do was sit there and wait. I scanned the faces in the room. Tom Harrigan rolled his eyes and shrugged.

"Are you reconsidering, Garret?" McCarthy said. "You shouldn't feel pressured to say anything." His tone suggested otherwise. "We can call it a night right now, if you want. Everyone will go home, like this never happened."

Garret looked up at him, glanced at me. A few more seconds of silence, then: "I was reading in my room. It was about eleven-thirty or so."

I felt my whole body relax. I sensed victory. I looked at Anderson. His fist was clenched. This was the moment we had worked for.

"I was reading and I heard something downstairs-from the basement," he went on. "It was a crash, like something had fallen."

McCarthy nodded encouragingly.

"I thought everyone else had gone to bed, so I was like, "That's weird,' you know? So I started going down to the basement." He squinted, as if visualizing the scene. "I got as far as the family room and I was walking toward the kitchen, where the basement door is. But before I got there I heard footsteps coming toward me. So I stopped. And Darwin walked into the room." Garret paused, looked directly at McCarthy. "He had a tube of plastic sealant in his hand."

Every trace of sound seemed to evaporate from the room. What Garret had said was enough to help Billy, but he wasn't finished.

"I told Darwin I had heard something in the basement," Garret continued. "He said not to worry about it, he'd knocked something over, to go back to my room."

"And what did you do?" McCarthy said.

"I went upstairs. But I had a bad feeling about the whole thing. Eerie, like. Darwin never goes down to the basement, first of all. And he seemed, like, out of it."

"Out of it," McCarthy repeated.

"Major league stressed or angry, or something," Garret said. "I couldn't tell."

"What happened next?"

"I heard him walk past my room, toward the nursery. So I waited until he'd gotten all the way down the hall, then I sneaked out of my room and followed him."

"And?" McCarthy said.

Garret closed his eyes. "I saw him take the tube of caulk and…"

"What did he do with the caulk?" McCarthy said.

"He put it in Brooke's nose. First on one side, then the other," Garret said. "Then down her throat." He opened his eyes. They were filled with tears.

It was the first time I had seen Garret cry. And for the first time, he seemed his age to me. He looked like an emotionally awkward, adolescent boy struggling to be a man, under the worst of circumstances.

"Then what happened?" McCarthy continued, unfazed.

"I went back to my room," Garret said, wiping tears off his cheeks.

"And you didn't tell anyone about this until now?" McCarthy said.

"No."

"Why not?"

"I was scared," Garret said.

"Of what?" McCarthy asked.

" Darwin."

"Why?"

"Because I've watched him beat my brother Billy almost unconscious," Garret said. "Because he's threatened more than once to kill me if I disobeyed him-let alone… turning him in."

"So why go out on a limb now?" McCarthy asked.

Garret swallowed, took a deep breath. "I saw what he did to my mother," he said, his lip starting to twitch again.

"If I had had the guts to stop him sooner, that never would have happened. I'm not going to wait until she's dead to do the right thing."

Garret left the interview room with a police escort. The plan was for him to stay the night in Boston, then head back to Nantucket.

State Police Captain O'Donnell was the first to speak. "Officer Anderson," he said, "based on what I just heard, along with the fingerprint evidence you obtained and the other circumstantial evidence in this case, I plan to charge Darwin Bishop with the first-degree murder of his daughter Brooke and the attempted murder of his daughter Tess." He glanced at Tom Harrigan. "I would presume the District Attorney's office will ask the grand jury to indict Mr. Bishop for those offenses, along with the attempted murder of his wife Julia earlier today."

"We'll be in front of the grand jury as soon as they can convene one," Harrigan said.

"I hope we can arrange Billy Bishop's release in the same time frame," Carl Rossetti said.

"We'll drop the charges against him as soon as possible," Harrigan said.

"When would that be?" Rossetti asked, stonefaced.

"I'll take care of it personally tomorrow morning," Harrigan answered.

Terry McCarthy looked over at Anderson and me. "That means Billy goes free in the a.m.," he said. "Would you two be picking him up?"

Anderson turned to me. "You mind taking care of that, Frank?" he said, with a wink. "I should get back to the island tonight."

"I don't mind," I said. "I don't mind at all."

As the room emptied, I pulled O'Donnell aside. "I think you owe me one thing," I said.

"What?" he said, annoyed. "You want some kind of formal apology? I should contact the newspapers, tell them how fucking brilliant you are? You haven't had enough news coverage in your life, Doc?"

"No," I said. "I'm not looking for anything like that."

He didn't walk away.

"He's gonna pay up," the voice at the back of my mind said. "He owes you the truth and he knows it."

"I meant what I said when we met at your office," I told him.

He smiled a surprised, good-natured smile. "That I'm a sociopath?" he said.

So he knew where we were headed. "Not that you're a sociopath," I said. "But that something got in the way of you doing the right thing here." I saw him stiffen. I shook my head and looked away, giving him a little space. "This is over," I said. "No hard feelings. All I want is the answer to one question." I looked back at him.

He took a deep breath, let it out. "Ask already." His eyes met mine and stuck.

"You've been through something painful," I said. "I want to know what it was."

The smile left his face. "Why? What does that matter to you?" he said.

"It does," I said.

"But why?"

"It just does." I could have said much more. I could have told him that, wherever I go, I keep searching for primary evil, out of the womb-the bad seed-but have never found it. I could have told him that everyone really does seem to be recycling pain, that empathy, properly harnessed, really does seem to stop the cycle of hurt-and heal people. And I could have told him that something about those two facts kept my mood from plummeting and kept me out of the gutter, because they reassured me we might be a worthwhile species, capable of more compassion than we seem to be. "If it turned out we were butting heads purely over some allegiance you've got to the mayor or Darwin Bishop, I just wouldn't know what to do with that. I wouldn't understand it, you know? I-"

"You need to know why people act the way they do. You want things to make sense," he said.

"Yes," I said.

O'Donnell chuckled, looked away. The smile on his face vanished. "I had a sister less than a year old kidnapped and killed by some bum drifter out of Colorado." He shrugged. "Maybe I wanted this case to go away. Maybe I shut down on it. My mistake." He glanced at me, then walked off.