I took the winding road down the backside of the hill and turned right on Promontory Drive, following the road along the ocean and through the back entrance to Horton Ravine. I used the next hour and a half canvassing the old neighborhood to see if anybody had been out and about on the night Isabelle was murdered. It didn't thrill me to be in range of David Barney, but I couldn't see a way around it and still get the information I wanted. A canvass by telephone is the same as not doing it. It's too easy for people to hang up, tell fibs, or shine you on.

One neighbor had moved and another had died. A woman on the adjacent property thought she'd heard a shot, but she hadn't paid much attention to the time and she'd later wondered if it hadn't been something else. Like what, I thought. I wasn't sure if it was my paranoia or not, but any time I heard what sounded like a gunshot, I checked the clock to see what time it was.

Of the eight remaining homeowners variously peppered along that stretch of road, none had been out that night and none had seen a thing. I got the impression that it had all happened far too long ago to bear worrying about at this point. A six-year-old murder doesn't engage the imagination. They'd already told their versions of the story one too many times.

I went home for lunch, stopping off at my apartment just long enough to check for messages. My machine was clear. I went next door to Henry's. I was looking forward to meeting William.

I found Henry standing in his kitchen, this time up to his elbows in whole wheat flour, kneading bread. Pellets of dough clung to his fingers like wood putty. Usually, Henry's kneading has a meditative quality, methodical, practiced, soothing to the observer. Today, his manner seemed faintly manic and the look in his eyes was haunted. Beside him, at the counter, stood a man who looked enough like him to be a twin; tall and slim, with the same snowy white hair and blue eyes, the same aristocratic face. I took in the similarities in that first glance. The differences were profound and took longer to assimilate.

Henry wore a Hawaiian shirt, white shorts, and thongs, his long limbs sinewy and tanned as a runner's. William wore a three-piece pinstriped suit, a starched white shirt, and a tie. His bearing was erect, nearly stiff, as if to compensate for the underlying feebleness I'd never known Henry to exhibit. William held a pamphlet in a slightly shaking hand and he pointed with a fork to a drawing of the heart. He paused for introductions and we went through the proper litany of inaugural sentiments. "Now where was I?" he asked.

Henry gave me a bland look. "William's been detailing some of the medical procedures associated with his heart attack."

"Quite right. You'll be interested in this," William said to me. "I'm assuming your knowledge of anatomy is as rudimentary as his."

"I couldn't pass a test," I said.

"Nor could I," William replied, "until this episode. Now Henry, you'll want to pay attention to this."

"I doubt that," Henry said.

"You see, the right side of the heart receives blood from the body and pumps it through the lungs, where carbon dioxide and other waste products are exchanged for oxygen. The left side receives the blood full of oxygen from the lungs and pumps it out into the body through the aorta…" The diagram he was using looked like the road map of a park with lots of one-way roads marked with black-and-white arrows. "Block these arteries and that's where you have a problem." William tapped on the diagram emphatically with the fork. "It's just like a rockslide coming down across a road. All the traffic begins to pile up in a nasty snarl." He turned a page in the pamphlet, which he held open against his chest like a kindergarten teacher reading aloud to a class. The next diagram showed a cross section of a coronary artery that looked like a vacuum cleaner hose filled with fluffies.

Henry interrupted. "Have you had lunch?"

"That's why I came home."

"There's some tuna in the refrigerator. You can make us some sandwiches. Do you eat tuna, William?"

"I've had to give it up. It's a very fatty fish to begin with and when you add mayonnaise…" He shook his head. "Not for me, thanks. I'll open one of the cans of low-sodium soup I brought with me. You two go ahead."

"Turns out William can't eat lasagna," Henry said to me.

"Much to my regret. Fortunately, Henry had some fresh vegetables I was able to steam. I don't want to be a bother and I said as much to him. There's nothing worse than being a burden to your loved ones. A heart condition doesn't have to be a death sentence. Moderation is the key. Light exercise, proper nutrition, sufficient rest… there's no reason to believe I couldn't go on into my nineties."