"Polaski couldn't tell he was talking with a stranger?" questioned Oates.

"They conversed from at least ten feet away from each other in low tones so they wouldn't disturb anyone on the yacht. When the 0300 post change came around, Brock simply melted into the fog.

Agent Polaski states that he was never able to see more than a vague figure. It wasn't until 0348 that agent Edward McGrath discovered that Brock was not at his scheduled post. McGrath then notified Blackowl, who met him on the Eagle four minutes later.

The yacht was searched and found empty, except for Polaski who had moved onboard to replace Brock."

Emmett placed the chalk back in the tray and wiped his hands together. "The rest is cut and dried. Who was alerted and when . . . the results of a fruitless search on the river and around the grounds of Mount Vernon . . . the roadblocks that failed to produce the missing men . . . and so on."

"What was the disposition of the tugboat and trash barges after the alert?" Metcalf questioned cannily.

"The barges were found moored to the riverbank," Emmett answered him: "The tug was gone."

"So much for facts," said Oates. "The prize question is How were almost twenty men spirited off the yacht under the noses of an army of Secret Service agents and passed undetected through the most advanced security alarm system that money can buy?"

"Your answer is, Mr. Secretary, they weren't."

Oates's eyebrows raised. "How was it done?"

Emmett noticed a smug expression on Metcalf's face. "I think the general has figured it out."

"I wish someone would tell me," said Fawcett.

Emmett took a deep breath before he spoke. "The yacht that agents Blackowl and McGrath found deserted is not the same yacht that carried the President and his party to Mount Vernon."

"Son of a bitch!" gasped Mercier.

"That's hard to swallow," said Oates skeptically.

Emmett picked up the chalk again and began diagramming.

"About fifteen minutes after the fogging generators began laying a dense cloud over the river and Mount Vernon, the abduction team transmitted on the Coast Guard's radar frequency and knocked it out of commission. Upriver the sanitation tugboat except in this instance it was not a river tug but a yacht identical in every detail to the Eagle-cast off from the barges, which we found to be empty, and slowly cruised downstream. Its radar, of course, was operating on a different frequency from the Coast Guard's."

Emmett drew in the path of the approaching yacht. "When it was fifty yards from the Mount Vernon pier and the stern of the Eagle, it shut down its engines and drifted with the current, which was running about one knot. Then the abductors-"

"What I'd like to know, is how they got onboard in the first place," Mercier interrupted.

Emmett made a shrugging gesture with his hands. "We don't know.