“The Glasgow . Commissioned in 1877 after the Sultan of Zanzibar lost his ‘fleet’ to the 1872 storm. It was delivered in the summer of 1878, but the Sultan was unimpressed, so it sat abandoned and unused at anchor off Zanzibar until the Anglo-Zanzibar War of 1896, when the British sunk her with naval gunfire.

“In 1912 the wreck was reduced to her bottom frames by a salvage company, and the majority of the pieces dumped at sea. In the seventies, the Glasgow’s engine block, propeller shaft, some crockery, and a few nine-pound shells were found on the site.”“Where’s the site?” Remi asked.

“About two hundred yards off the Stone Town beach. In fact, you were within sight of it at the restaurant the other night.”

“So about fifteen crow’s miles from where we found the Ophelia ’s bell,” Sam said. “So scratch the Glasgow. What else?”

“Four of the wrecks in the database are unidentified. One is sitting in the Pangani River thirty-five miles to the north; the next two are in Tanga Bay fifty miles to the north; the last one is sitting off Bongoyo Island in Dar es Salaam’s Msasani Bay. As far as I can tell, none of them is any deeper than thirty feet.”

“Thirty feet of clear water,” Sam added. “We’ll check with area dive shops. Chances are, someone’s identified them but never bothered to say anything. Probably nothing more than dive attractions now.”“Sorry I came up empty,” Selma said.

“You didn’t,” Remi replied. “Ruling out is just as important as ruling in.”

“Two other things. Mrs. Fargo, you were right about those names, they are Nahuatl, traditional Aztec names. For what it’s worth, it’s been something of a trend in Mexico City for the last few years-”

“The Mexica Tenochca Party,” Remi finished. She saw Sam’s confused expression, then added, “The current president is an ubernationalist, a pre-Spanish invasion nationalist. Aztec names, history courses taught in schools, religious observances, art . . .”“In addition to everything else, Rivera and his pals are political zealots,” Sam replied drily. “Just what we need.”

“What else, Selma?”

“I studied the pictures of the bell you sent. I assume you noticed the clapper?”

“You mean that it’s missing?” Sam asked. “We noticed.”

Sam disconnected, then turned to Remi. “So, newspapers?”

She nodded. “Newspapers.”

SAM AND REMI WERE believers in the pyramid theory of research: Start with the top of the pyramid, the specific, and work your way down to the base, the general. The first search terms they tried were “Ophelia,” “wreck,” and “discovered.” Not surprisingly, all they got were stories Selma had covered. Next they tried “famous,” “shipwrecks,” and “Zanzibar” and got the expected results: fluff stories about the Glasgow and the El Majidi, another ship belonging to the Sultan of Zanzibar that had been lost during the 1872 hurricane, and the HMS Pegasus, sunk in 1914 following a surprise attack by the German cruiser Konigsberg .Ms. Kilembe returned with a carafe of coffee and two mugs, asked if they needed anything, then disappeared again.

Remi said, “We forgot Chumbe Island, Sam. We’re assuming the BBC interview brought Rivera here . . .”

“Right.” Sam combined the previous search terms with “Chumbe Island” and got zero hits. He tried again with the terms “diving,” “artifact,” and “discovery.” He scrolled through the stories, then stopped. “Huh,” he muttered.“What?”

“Probably nothing, but it’s curious. Two months ago a British woman named Sylvie Radford was found murdered in Stone Town. An apparent mugging gone wrong. She’d come to do some diving off Chumbe. Listen to this: ‘According to the woman’s parents, Ms. Radford had been having a wonderful diving vacation, having already found several artifacts, including what she thought might be part of a Roman-style sword.’”

“‘A Roman-style sword,’” Remi repeated. “Interesting. Her words or the reporter’s, do you think?”

“I don’t know. Either way, it’s a pretty specific description. Most laypeople would just say ‘sword.’”Remi leaned closer to the screen, then jotted down the reporter’s name. “It might be in her notes.”

Sam started tapping the keyboard again, this time with some urgency. Into the search box he entered “southern,” “Zanzibar,” “diving,” and “death” and set the time frame from present day to ten years earlier. Dozens of stories appeared on the screen.“Let’s split them up,” Remi said, then typed the terms into her own search box. “Start with the oldest?”

Sam nodded.

In years ten through eight, four deaths were linked to their search terms. In each case, however, independent eyewitness reports confirmed they were accidental: one shark bite, one diving mishap, and two vehicle accidents, both involving alcohol.“Here,” Remi said. “Seven years ago. Two people, both tourists on diving vacations.”

“Where exactly?”

“It just says the southwest coast of Zanzibar. One of them was killed by a hit-and-run driver. The other one fell down some steps in Stone Town. No alcohol involved, no witnesses.”“Six years ago,” Sam said, reading from the screen, “two dead. One suicide, one drowning. Again, no witnesses.”

And so it went with year five up to the present day: tourist divers, most of them spending time near or around Chumbe Island, dying in strange accidents or muggings gone wrong.“I count five,” Remi said.

“I’ve got four,” replied Sam.

They were silent for a few moments.

Remi said, “Has to be a coincidence, right?” Sam simply stared at his screen, so Remi said, “Otherwise, what are we saying? Rivera and whoever he works for have been murdering divers that show an interest in Chumbe Island?”

“No, it can’t be that. They would number in the hundreds . . . the thousands. Maybe it’s the people who declare their finds. Or take them to local shops for identification. If we’re right about this, these people have to have something else in common.”“They told someone about what they found,” Remi offered.

“And it was the right kind of artifact, something to do with the Ophelia . Or the ship with the blotted-out name.”

“Either way, if she’d sunk off Chumbe, artifacts would be washing up on the beach. Every monsoon there would be debris just sitting on the bottom waiting for someone with a Ping-Pong paddle to come along.”

“True,” said Sam. “But there are plenty of people who find something and never mention it. They go home and put it on their mantel as a souvenir. In fact, that describes most casual treasure divers: They find something, make a minor effort to identify it, but if it’s not something obviously ‘treasure-ish’ they treat it as a keepsake . . . ‘Our week in Zanzibar.’”“This is a huge leap we’re talking about, Sam.”

“I just remembered something: Rivera said he’s been looking for the Ophelia for seven years.”

“About the same time the strange deaths started.”

“Exactly. I need to call Rube. We need to find out how good Tanzanian immigration and customs are at recordkeeping.”

SAM MADE THE CALL and explained their request to an incredulous but willing Rube Haywood, who said, “So your theory is that Rivera was in Zanzibar around the time all the deaths would have taken place?”“It’s worth a shot. Even if the records don’t show he was here every time, he may not have traveled under his own name.”

“I’ll look into it. Wouldn’t hold your breath.”

Sam thanked him and disconnected.

A few minutes later Ms. Kilembe knocked on the door and peeked her head inside. “Do you need anything?”

They thanked her and declined. She was turning to leave when Sam asked, “Ms. Kilembe, how long have you been with the library?”“Thirty years.”

“And how long in this area?”

“All my life. I was born in Fumba, on Zanzibar.”

“We’re looking for anything on a ship called Ophelia . Does that name mean anything to you?”

Ms. Kilembe furrowed her brow. After ten seconds of thought, she said, “I assume you’ve been to the Blaylock already?”