"I understand," he said. "You've got people whose health and safety have been compromised. On the bright side, we do have a couple of things that might help us narrow the search."

"Tell me," I said. "I could use some good news."

"Remember, the half-life is just seventy-four days. So if you put a fresh two-hundred-curie source in your RadioGraph Elite, seventy-four days later it's down to a hundred curies, and by a hundred and forty-eight days it's down to fifty curies. At the end of a year, that stuff has decayed through five half-lives, so it's down to six curies. Knowing the source in Novak was still around a hundred curies tells us something very useful."

"It tells you the source was fresh," I said. "And it tells you it wasn't from one of those cameras that went missing in Katrina."

"Bingo," he said.

"So who actually makes the sources?" I said. "And how, and where, and when? Does this outfit in Shreveport have a reactor or a cyclotron or whatever is used to make iridium-192? Do they make big batches of these things-hundreds of things at once?-or just a few at a time? How hard can it be to track down everybody who got one sometime in the past three months?"

He smiled at the burst of questions. "It's harder than I wish it were," he said. "That's why we've got a hundred people working on it. You know the old saying about the tip of the iceberg?" I nodded. "Well, I'm just the guy standing on top of the tip of the iceberg. Everything below is shrouded in fog."

Just then his cell phone rang-an odd, warbling tone I'd never heard from a cell phone before. He looked startled, then murmured, "Excuse me." He turned his back on us and spoke softly, but I could make out a few words, mostly "yes sir" and "no sir" and "thank you, sir." He ended the call with a promise to phone with an update before the end of the day. He turned back to us, looking somewhere between embarra.s.sed and sh.e.l.l-shocked. "I'm sorry," he said, "I had to take that. The man calls, you answer."

"Which man?" I asked. "Your boss? The head of the WMD Directorate?"

"His boss's boss's boss," said Thornton. "The director. Of the FBI. He wants progress reports three times a day. This case is a big target on his radar screen."

I felt a sudden tightening in my throat, and a sudden surge of hope that we'd find out who had killed Novak-and who might be slowly killing Garcia.

CHAPTER 20.

THE NEXT MORNING MIRANDA AND I HAD A SHORT but cheerful visit at the hospital with Garcia. Garcia still looked weak, his burned hands were quite tender, and his lymphocyte count remained dangerously low, yet his spirits were surprisingly high. He was six chapters into a sterilized copy of The Making of the Atomic Bomb, one of the books I'd seen on Leonard Novak's desk. The book was propped on a reading stand, and Garcia was turning the pages with the eraser of a pencil, which he managed to grip with his bandaged right fist. "Great book," he said. "Those Manhattan Project scientists were big thinkers. Complicated human beings, though." I was surprised at his choice of reading material, but delighted to see him in good spirits.

After leaving the hospital, we returned to the bone lab. We'd just started reconstructing the cranium of the North Knoxville skeleton when Chip Thornton came knocking on the door. "Wow," he said. "Skeleton in a kit. Looks like fun."

Miranda made a face at him. "You came to help?"

"Yes," he said. "Okay, no, that's a lie. I was in the neighborhood and figured it was just as easy to relay this in person as on the phone." That's a lie, too, I thought. You figured you'd stop and flirt with Miranda. "We've had some people digging out old security files," he said, "and they found an interesting note in Dr. Novak's. Apparently there was some suspicion at the time that Novak was a h.o.m.os.e.xual. Army intelligence recommended that he be removed from the project as a security risk, but General Groves himself nixed it-he wrote that Novak could consort with farm animals as long as he produced sufficient plutonium in the reactors in Oak Ridge and Hanford." Miranda looked appalled. My guess was that her disgust had less to do with the notion of interspecies love than with Groves's readiness to ridicule the scientist at the same time he was depending on him.

"Poor Novak," she said, confirming my thinking. "What on earth was he doing in the boonies of Tennessee?"

"It's where the project was," said Thornton. For such a smart guy, he had an unfortunate tendency to take things too literally at times. "Groves picked Oak Ridge as the main site for the Manhattan Project for a bunch of reasons," he said. "Far enough inland that the Germans and j.a.panese couldn't possibly attack it. Isolated enough to stay below the radar screen. Good access to rail lines and cooling water and hydroelectric power and a civilian workforce." I nodded; I'd read this in several of the history books I'd hauled back from the Oak Ridge library in the past week. "I don't know if this was another factor in the selection," he went on, "or just something that Groves came to appreciate as the project progressed, but folks in Appalachia tend to be pretty tight-lipped."

Miranda pursed her lips, then said, "Yup." Thornton and I laughed.

"Conservative, too," he said. "Oak Ridge was practically the polar opposite of Los Alamos. Los Alamos was filled with loose-lipped liberals, from the top down. h.e.l.l, up until Groves put him in charge of Los Alamos, Robert Oppenheimer gave money to Communist causes. Oppenheimer's wife, Kitty, was a member of the Communist Party. So was his younger brother, Frank. So was Oppenheimer's girlfriend, until she committed suicide."

"Wait, wait," said Miranda. "Girlfriend as in 'before he married Kitty'? Or girlfriend as in 'running around on Kitty'?"

"Maybe both," said Thornton. "He was engaged to a woman named Jean Tatlock before he married Kitty, and he stayed in touch with her occasionally afterward. One of the creepier things in Oppenheimer's file is a report by an army intelligence agent, Boris Pash, who followed Oppenheimer from Los Alamos to Berkeley in June of 1943. Pash watched Oppy go inside Tatlock's apartment, wrote down what time the lights went out, and then wrote down what time they came out of the building the next morning."

"Yuck," said Miranda.

"It might seem intrusive," conceded Thornton, "but these guys were working on a life-and-death, fate-of-the-nation project. Oppenheimer was in the most sensitive position of all the scientists. And Berkeley, where he and a bunch of other Los Alamos scientists came from, was a hotbed of communism. You think Berkeley was leftist in the 1960s and 1970s, you should've seen it in the thirties and early forties."

"If the choice is between peeping Toms and left-wing liberals," said Miranda, "I'll take the Berkeley crowd any day."

"Swell place," said Thornton, "if you like Marx and Lenin." I heard a faint warning bell begin to ring in the back of my mind, but I shrugged it off. "Oppenheimer and the people he brought to Los Alamos were brilliant, no doubt about it," the agent continued. "They were the ones who put the pieces of the bomb together. But Los Alamos leaked like a sieve. Oppenheimer ran Los Alamos sort of like a university physics department. He held seminars where people talked openly about the bomb. He gave folks a mimeographed handout-The Los Alamos Primer, it was called-that summed up everything they knew about how to build an atomic bomb."

"Probably helped speed things along," said Miranda. "Synergy, cross-fertilization of ideas, intellectual critical ma.s.s-all that stuff we liberal ivory-tower types believe in, you know?"

Thornton frowned at her slightly; he didn't seem to approve of the handout, and he didn't seem to like the edgy comment, either. "It might have helped speed the Manhattan Project, but it also helped speed the Soviets," he said. "One of the Los Alamos physicists, Klaus Fuchs, gave a copy of the primer, or the key details from it, to a Soviet intelligence agent in June of 1945. It was like handing over a set of blueprints for the bomb. The guy betrayed us for five hundred bucks."

I wasn't sure I'd heard correctly. "Five hundred dollars? The Soviets got America's atomic secrets for five hundred dollars?"

He nodded. "I like Oak Ridge," he said. "Oak Ridge was way bigger than Los Alamos, but a lot tighter-lipped. A lot more compartmentalized, too. Most people didn't know what they were working on. They tended not to talk about it or speculate about it. And if they did, they got escorted out the gate, because anybody they talked to could have been a snitch."

"A snitch?" Miranda sounded offended by the word. "What makes you say snitch?"

"Only word for it," he said. "Security was a huge priority in Oak Ridge. There were hundreds of military intelligence officers in Oak Ridge. Some in uniform, some not. Some had cover jobs-they went around testing batteries and changing lightbulbs, menial work that let them watch and listen to workers all over the place. But the serious snitching was the Acme Credit Corporation."

Miranda snorted. "Acme? How corny is that? Sounds like something from a Road Runner cartoon."

Thornton smiled slightly. "It does sound corny these days, doesn't it? It might not have sounded so corny back then-back before Road Runner. Back in the middle of a struggle for world domination."

Miranda flushed slightly. "Sorry," she said. "I didn't mean to get all cynical and ironic on you. What was the Acme Credit Corporation?"

"A bogus name and a post-office box in Knoxville," said Thornton. "If the military intelligence people decided you were trustworthy-from your background check or their eavesdropping or whatever-they'd ask you to keep your eyes and ears open, and report anything that seemed suspicious. If you agreed, they'd give you these preaddressed ACME CREDIT CORPORATION envelopes and blank cards, and if you thought something or somebody seemed fishy, all you had to do was jot down their name and what they said or did on the card, then drop it in the mail. If you didn't see anything, you sent in a blank card. Every tip got investigated."

Miranda leaned back in her chair and bit her lower lip slightly. In my experience, anytime she did that, an argument was about to ensue. "What kind of fishiness? 'So-and-so is making bombs in his bas.e.m.e.nt' fishiness? Or 'so-and-so likes to wear his wife's underwear' fishiness?"

"Probably some of each," he said. "One episode I heard about involved a fellow who was spouting off at lunch one day about the Soviet system of government being better than the American system. A day or two later, Acme got a note, and the guy was gone-given his walking papers and told not to come back."

"Whatever happened to freedom of speech?" Miranda was shaking her head. "Sounds a lot like East Berlin during the Cold War, the way people ratted out their friends and neighbors to the Stasi."

"Oh, come on," said Thornton. "We were in the midst of a horrific war. Global, apocalyptic war. Secret codes, spies, sabotage-those were real things, legitimate concerns. A slight erosion of civil liberties in a top secret military installation seems pretty far down on the list of World War II evils, if you ask me."

"Children, childen," I said. "Let's not bicker." I heard Miranda draw a deep breath, and saw her relax, which meant Thornton and I could relax, too. "Does the army have a card that could tell us why Leonard Novak was reading books on espionage when he was killed?"

"That's what I'm hoping," he said. "We've got people combing the Venona transcripts to see if they can find anything that might connect with Novak."

Miranda looked puzzled. "Venona was the code name for a ma.s.sive counterespionage operation," Thornton explained. "Between 1944 and 1948, the agency that's now called the NSA-the National Security Agency-intercepted and decoded thousands of telegram cables sent to Moscow from Soviet consulates around the world. Most of them were boring, bureaucratic stuff. But some, especially the ones from New York to Moscow, were spy reports. They used code names for people and places-the messages were in code, so the names were codes within codes-but the code-breakers eventually managed to decipher most of them. Amazing feat, really, because the Soviets were using complicated codes that changed every day. Crypta.n.a.lysists have extra gears in their minds-like physicists-that help them grasp things we mere mortals can't make sense of. Anyhow, one of the interesting intercepts was telegram 940-"

"Telegram 940? I like it," Miranda interrupted. "It even sounds like something from a spy thriller." She was leaning forward on the table, rapt with attention now. Thornton smiled, pleased to have won her over, or relieved that she was off her civil-liberties high horse.

"Telegram 940 was sent in December 1944," he said. "It listed seventeen scientists who were working on what it called 'the problem.' The names included Enrico Fermi, Hans Bethe, Nils Bohr, George Kistiakowsky, Ernest Lawrence, Edward Teller, John von Neumann, and Arthur Compton-some of the top brains of the Manhattan Project."

I held up a hand, which I practically had to wave directly between Thornton and Miranda to catch his attention. "I know some of those names," I said, "but not all. Fermi was the guy who cobbled together the little reactor under the stadium in Chicago. But Bethe and Bohr-remind me. Physicists?"

"Right," he said. "They were in the Theoretical Division at Los Alamos. Bohr was a n.o.bel laureate-so were Lawrence and Fermi, of course. Bohr escaped from Denmark under the noses of the n.a.z.is, who were hoping to recruit him. He made it to London, then he and his son were flown to the States in an army transport plane."

"Edward Teller," said Miranda. "I'm not a fan of his."

"No, I wouldn't expect you to be," he said. "Teller's big claim to fame came in the late forties and fifties, of course, when he pushed for the hydrogen bomb-the 'super,' he called it-over the objections of Oppenheimer. Back during the Manhattan Project, Teller and von Neumann helped develop the implosion trigger for the plutonium bomb, the one used on Nagasaki." I saw Miranda's eyes cloud at the mention of Nagasaki; I'd noticed that anytime a discussion turned from the herculean labors of the Manhattan Project to the explosive fruits of those labors, it troubled her.

I tossed in another question, hoping to lead us away from Nagasaki. "How about Kistiakowsky? I never heard of him."

"Interesting guy," said Thornton. "Explosives expert. He cleared the first ski slope in Los Alamos by using rings of explosives to cut down trees."

"Cool dude," said Miranda. "See, that's a use of explosives I can really get behind." I was just congratulating myself on asking about Kistiakowsky when Thornton dropped the other, unfortunate shoe.

"Kistiakowsky was one of the unsung heroes of the project, if you ask me," he said. "He was the bridge between the pie-in-the-sky theoretical physics and the nuts-and-bolts realities of building the bomb-the 'Gadget,' they called it in Los Alamos-and making it actually explode. Kistiakowsky came up with what's called the implosion lenses for the plutonium."

"Lenses?" I hadn't known the atomic bomb involved optics.

"Not really lenses," he said. "That was the term they used for wedges they formed out of conventional high explosives. The lenses surrounded the spherical core of plutonium. The theory was, when the lenses exploded, they'd create a very focused shock wave, which would compress the plutonium enough to cause critical ma.s.s."

"And kablooey?" The edge on Miranda's question was so fine as to be nearly invisible. I noticed it, but Thornton didn't.

"Kablooey," he said, with unfortunate cheerfulness. "But the wedges, the lenses, had to be machined with incredible precision-like, accurate to zillionths of an inch. n.o.body thought Kistiakowsky could do it, including Oppenheimer. In fact," he went on, warming to the story, "one reason they did the Trinity test with a plutonium bomb was because they were confident the uranium bomb would work but afraid the plutonium bomb would be a dud. Poor Kistiakowsky was already being set up as the scapegoat for failure. He finally got so fed up with the skepticism that he bet Oppenheimer a whole month's pay-against just ten bucks from Oppenheimer-that it would work. And of course it did."

"So Kistiakowsky got his ten bucks," said Miranda, "and Nagasaki got vaporized." Her voice dripped sarcasm. "A real win-win."

"Could've been worse," said Thornton, finally punching back. "Fermi could've won his bet."

Oh h.e.l.l, I thought, here we go.

"And what was Fermi betting," she snapped, "that maybe we'd come to our senses and not use the d.a.m.n thing on innocent civilians?"

"Guys, guys," I said, trying to de-escalate the conflict, but the chain reaction had gotten out of hand.

"No," shot back Thornton. "Fermi was betting the bomb would ignite the atmosphere. He was taking side bets, too: Would it incinerate the whole world, or just New Mexico?"

"Jesus," said Miranda. "That is sickening."

"You. Weren't. There." Thornton's voice was quiet but hard as steel. "How dare you judge them? How dare you? You and I are part of the most sheltered, pampered generation ever to walk the face of this earth. These scientists, a lot of them, were refugees, Jewish refugees, from Europe-the land of Hitler, the land of the Holocaust, remember? Six million Jews murdered, just for being Jews. Tens of millions of other civilians killed just for living in the wrong place, the wrong time, the wrong politics. If those scientists felt the need for a little gallows humor, who can blame them? The gallows was casting a shadow over the whole d.a.m.n world at the time. How dare you sit there in your privileged, liberal smugness and pa.s.s moral judgment on them?"

Miranda drew back as if he'd slapped her. "Excuse me," she whispered. She stood up, and before I knew what was happening, she was gone, the steel door of the bone lab banging shut behind her.

Thornton and I sat staring at each other. "Well, s.h.i.t," he finally said. "I just scorched the earth, didn't I?"

"I should've stopped you somehow," I said. "Kicked you under the table. Clobbered you with a femur."

He rubbed his face with his hands. "The h.e.l.l of it is, I really like her," he said. "I thought maybe she liked me, too."

"She did," I said. "And she's notoriously picky."

"c.r.a.p."

"Oh well," I said. "You'll always have Paris. Or Verona. Or Venona. Was there anything else about Venona or Novak or-I don't know, about anything-you'd planned to tell us, before you went stomping across the minefield of Miranda's opinions?"

He sighed. "A little," he said. "Nothing concrete yet; just some tantalizing possibilities. There are lots of code names in the Venona transcripts that have never been deciphered-hundreds of Soviet spies in the United States back in the forties that have never been identified. We're hoping, if we sift back through the transcripts again, maybe we'll get lucky; maybe find something that ties to Novak."

"Not to be too negative," I said, "but if they threw thousands of people and millions of dollars at this back when it really mattered, isn't it likely to be a dead end by now?"

"Not necessarily," he said. "New things still bubble up. Just a couple years ago, we got some new insight on one of the few spies who infiltrated Oak Ridge. A health physicist, guy named Koval, who worked at Oak Ridge and Los Alamos and Hanford during the war. His job was checking radiation levels, so he got a look at all the crucial process equipment for creating weapons-grade uranium and plutonium, and n.o.body suspected him at the time, even though he'd lived and studied in Russia."

"I thought you said security in Oak Ridge was tight. They turned a Russian loose with a Geiger counter?"

"His parents were Russian immigrants, but Koval was an American, actually-born in Iowa, and christened George. Millions of European and Russian immigrants came to the U.S. in the early part of the twentieth century-the 'huddled ma.s.ses yearning to breathe free,' remember? Koval's parents were among them."

One of the notations on Leonard Novak's yellow notepad popped into my head. "George Koval?" Thornton nodded. "Novak wrote the initials 'GK' shortly before he died, and he was reading books about Venona at the time. Maybe he knew about Koval. Maybe they collaborated. Can you guys interrogate George, see if our guy Novak was one of his comrades?"

"George is outside our jurisdiction," Thornton said dryly. "Moved to Moscow in 1948, died in 2006. After he died, Vladimir Putin awarded him Russia's highest medal."

"d.a.m.n," I said. "Well, between the Acme Credit Corporation and the Venona transcripts, maybe something will turn up."

He gave a rueful smile. "Unlike Kistiakowsky, I wouldn't bet a month's pay on it," he said. "h.e.l.l, I wouldn't bet ten bucks. But we'll keep digging." He thought of something. "You still in the good graces of the woman in Oak Ridge?"

I blushed. "The librarian? Isabella?"

He shook his head. "No, the old lady. Beatrice. The one that married Novak without having done due diligence about his s.e.xual orientation."

"Ah. No, I haven't talked to Beatrice since she outed Novak as gay, but it's not like she and I have had a spat."

"Lucky you," he said. "Listen, since you seem to bring out the gift of gab in Madame Beatrice, how about chatting her up some more, see if she thinks Novak was giving secrets to the Soviets?"

"If she snitches on him, should I send a note to the Acme Credit Corporation?"

"Sure," he said. "We check the P.O. box twice a day." He pushed back from the table. "I reckon I'll slink back to my office now," he said. "I've done enough damage here for one day."

"You mean Miranda?" He nodded. "Surely you're not throwing in the towel so soon," I said. "I thought you G-men never gave up. 'We always get our man'-wasn't that an early FBI slogan?"

"Nah, that was the Canadian Mounties," he said. "They had a better sloganeer than we did. Besides, this thing with Miranda, it's outside my field of expertise. The bad guys, they're pretty easy to figure out, Doc. It's the great women that are truly mysterious."

"I know, Chip," I said. I walked him to the door of the lab. "That's what makes them great."

CHAPTER 21.

FOUR HOURS AFTER THE BLOWUP IN THE BONE LAB, AS I was about to head to Oak Ridge for another stroll through the past with Beatrice, I heard a light tap on my door. Looking up, I was surprised to see Miranda; normally she just barged right in, her arrival accompanied by a wisecrack-usually one at my expense. Her eyes were red and she looked off-balance. I pointed to an empty chair that was shoved against the radiator under the window.