"It wasn't until this time yesterday that our security systems detected a difference in the speech pattern of Captain Burch's voice during his status reports to NUMA headquarters. Until then the reports were accepted as genuine. We had no cause for suspicion."

"When we left the ship, all was normal."

"The last report by the genuine Captain Burch said the Abyss Navigator was about to be lowered in the water. We know now the hijackers boarded while you were on the bottom."

"Do you have any idea where the ship was taken?" asked Giordino.

"No," Gunn said candidly.

"It couldn't have evaporated," said Misty. "It wasn't swept into space by aliens."

"Our worst fear," Sandecker said ominously, "is that she was intentionally sunk." He pulled back from suggesting that the entire crew might be lying under the sea.

"But why?" questioned Giordino. "What earthly good is an oceanographic survey ship to pirates? There is no treasure on board. The ship can't be used for smuggling. It's too slow and too recognizable. Where's the motive?"

"Motive . . ." Pitt let the word slide off his tongue and hang in the air. "The same people who torched the cruise ship and then sank her wanted to prevent us from discovering evidence of arson."

"Were you able to survey the wreck?" asked Gunn.

He nodded. "There's no doubt about it, the bottom was blown out of the Emerald Dolphin in at least six places, sending her to the bottom of the Tonga Trench."

"From what I've heard," said Sandecker, "she came within a hair of taking the tugboat with her."

Giordino said slowly, "Twenty thousand feet deep in the ocean makes for a pretty effective hiding place."

Gunn said, "The murderous scum never figured on a NUMA survey ship working in the area, one with a pair of submersibles that could go down twenty thousand feet."

Misty's eyes suddenly looked stricken. "Which brings us to the horrible possibility that everyone on the Deep Encounter has been killed in the cover-up."

There was silence on the yacht and ten thousand miles away in Washington. They were all loath to consider the prospect. There was no doubt in their minds that anyone who lacked a conscience about burning alive or drowning everyone on board a cruise liner would have any hesitation about sending the survey ship and its crew to the bottom of the sea.

Pitt's perspective began to focus. He considered every avenue and gambled that the pirates had not yet set their murderous plan in gear. "Rudi?"

Gunn removed his glasses and began polishing the lenses. "Yes."

"The pirates could have just as easily sunk the Deep Encounter after they captured it. But you say they faked voice transmissions of Burch giving his scheduled reports. Why would they have bothered to stall off any suspicion if the ship was already sunk?"

"We don't know that it wasn't sunk," said Gunn.