He could no longer see the U.S. embassy cars, but there was a police car down Arlington Street beyond the Blue Posts. At the bottom of the steps, on the sidewalk, the doorman was speaking to a uniformed London cop.

The traffic was still light, but it was now flowing along Bennett Street, through Arlington to the Piccadilly throughway. Ravi permitted himself three guesses-a luxury in which he rarely indulged. The first was that the police snipers were still on duty on the roof of the building; the second was that Reggie was at his desk in the foyer. The third was that Admiral Morgan’s car would be summoned by phone when he left the Ritz, and that the security detail would make certain that he and his wife were quickly into the vehicle. His fourth thought was an assumption, not a guess: that his “window” of opportunity would again be very short-lived, but less crowded.

It was only just 8 A.M., but people were beginning to arrive. Ravi could hear the elevator creaking as it went up, but it made no noise as it descended. If the two cops, the ones he assumed were still on the roof, left via the elevator, he would not know they had gone.

Equally, Reggie did not know Ravi was in the building. No one did, and the last image Reggie had in his mind, concerning Mr. Fretheim, was from yesterday, of a man in a loose-fitting dark blue tracksuit, wearing sneakers and carrying a sports bag. Images were critical in operations like this, because they affected the memory, shaded the truth, and distorted the reality.

Ravi poured himself the last of his coffee and ate the remaining two chicken sandwiches. He did so in front of the window, from an area to which he had shifted his chair. When he stood up, he slipped the window catch and pushed upward. The old-fashioned lower section rose, and Ravi kept pushing until it was open all the way.

If the security men were scanning the front of this building, they would not notice the lower open window, because it was fully open. He adjusted the Venetian blind so the light breeze from the southwest would not cause the laths to rattle.

While Arnold and Kathy slept, Ravi made his final preparations. He realized the Americans might not leave the hotel until after lunch, maybe not until tomorrow, and during this time he would be a virtual prisoner in this office. He resolved to change clothes at 10:30 A.M. and take up his position at the window immediately afterward. He would not move again.

And now he peeled off his tracksuit and sneakers. He pulled a dark gray suit out of his bag, plus a new shirt, tie, and shiny black loafers. He dressed carefully and slung the suit jacket over the back of his chair. Everything else, except for the briefcase, he crammed into the duffel bag, which he left behind the office door.

Inside the suit pockets he had crammed cash, an English driver’s license in the name of Michael Barden, and a British passport to match. It stated his birthplace as Maidstone, Kent. In the wallet was an American Express card under the same name, on an account registered, if anyone was looking, to the attaché at the Jordanian embassy in Paris. Credit limit: 100,000 euros.

Ravi would need only to dispose of the duffel bag, and now he went to the briefcase, released the catch, and opened it wide on the desk. He took out the barrel of the SSG 69 and carefully began to assemble the rifle. He handled it lovingly, the instrument of his holy mission. The pieces slotted and screwed together perfectly.

When it was completed, he loaded the six silver-headed bullets, five into the breech, one into the firing position in front of the bolt. His last actions were to clip on the telescopic sight and the silencer, which he did with practiced expertise. He balanced the weapon in his hands and smiled at the memory of the final shots in the Long Wood out in Oxfordshire. If he could get a clear view, with this rifle he could not miss.

Eleven o’clock came and went, and still Ravi stood motionless before the window, staring at the Ritz entrance, watching hotel guests come and go, up those six steps. Taxis came. Taxis went. Chauffeurs pulled up, helped people with baggage, and departed.

At 11:30, Admiral Morgan’s bald bodyguard stepped out of the hotel. He said one quick word to the doorman, who immediately stepped out into the street, raised his arm, and signaled for a car. Ravi heard him blow hard on a whistle.

From way down Arlington Street, the embassy car with the darkened windows came sliding along to the Ritz. Four police outriders led the way. Inside the lobby, Admiral Morgan was telling his other three agents that it was such a beautiful morning, he and Kathy would prefer to stroll along to Hatchards. All three of them objected, telling him that with a terrorist alert in progress, it would make everyone much happier if he were given safe passage in the big bulletproof embassy car.

“Goddamned Ramshawe still causing trouble,” said Arnold ruefully. “He’s been waiting for this moment for a month, trying to curtail my simplest pleasures.”

“Darling, don’t talk about him like that,” scolded Kathy. “He cares about you more than anyone in the world, except for me. He is genuinely worried, as you well know.”

“I know all that, but he’s still a goddamned nuisance,” replied her husband. And he turned to Big George, his new bodyguard, and demanded, “And where the hell do you think you’re going to park that thing while I’m in the bookstore? In the biography section?”

“Don’t worry about that, sir. The car will be right there when you come out. I’m only following orders. The president insists you play everything by the book while we have this terror threat.”

Admiral Morgan scowled. But did as he was told. George checked outside. “Car’s here, Admiral,” he said. “Let’s go.”

Kathy took Arnold ’s right arm, and the five of them walked across the carpeted lobby. George went through the revolving doors first, followed by the other two guards, then Kathy, last of all the admiral.

From high above, Ravi leveled the Austrian precision rifle at the Ritz entrance. One by one he watched them emerge, gravitating to the right-hand brass rail. The doorman, however, was standing on the left, and when the admiral himself came out, he stood next to the doorman as Kathy took his right arm. They started down the steps, and the moment Arnold moved forward, Ravi had his clear head shot, for less than one second.

But Big George, sensing the admiral’s unprotected left flank, suddenly swung around on the fourth step down and took a giant stride back up to Arnold ’s left.

Ravi tensed, kept the rifle steady, the crosshairs on the admiral’s head, and pressed the trigger. The sound was a soft phutt. The 7.62-millimeter shell ripped out of the barrel just as George reached for Arnold ’s arm, stepped across, and completely blocked him from the left.

The bullet caught the big bodyguard full in the temple, splitting the skull right in front of the hairline, penetrating the brain, exploding on impact inside his head. George died while he was still holding on to the left-hand brass rail.

He pitched forward, pushing Arnold and Kathy to the right and falling into the top step, his neck twisted. The small wound to his left temple was obscured. And for at least five seconds, no one had the slightest idea what had happened. Then the blood began to trickle down the steps.

All three remaining agents formed a cordon around the admiral, one of them shouting, “Police! Right here we have a shooting! One of our guys is dying!”

The doorman blew his whistle and the agents hustled Arnold down the steps and almost hurled him into the embassy car. The police outriders swung around and drove the motorbikes into tight formation around the vehicle. With Arnold now onboard, the American agents raced up the steps to collect Kathy, who was standing next to the doorman.