Still, Green was determined to dig deeper for his now highly anticipated biography. As the mystery writer Iain Pears has observed, Conan Doyle’s hero acts in nearly the same fashion as a Freudian analyst, piecing together his clients’ hidden narratives, which he alone can perceive. In a 1987 review of Conan Doyle’s autobiography, “Memories and Adventures,” which was published in 1924, Green noted, “It is as if Conan Doyle—whose character suggested kindliness and trust—had a fear of intimacy. When he describes his life, he omits the inner man.”

  To reveal this “inner man,” Green examined facts that Conan Doyle rarely, if ever, spoke of himself—most notably, that his father, an epileptic and an incorrigible alcoholic, was eventually confined to an insane asylum. Yet the more Green tried to plumb his subject, the more he became aware of the holes in his knowledge of Conan Doyle. He didn’t want just to sketch Conan Doyle’s story with a series of anecdotes; he wanted to know everything about him. In the draft of an early mystery story, “The Surgeon of Gaster Fall,” Conan Doyle writes of a son who has locked his raving father inside a cage—but this incident was excised from the published version. Had Conan Doyle been the one to commit his father to the asylum? Was Holmes’s mania for logic a reaction to his father’s genuine mania? And what did Conan Doyle mean when he wrote, in his deeply personal poem “The Inner Room,” that he “has thoughts he dare not say”?

  Green wanted to create an immaculate biography, one in which each fact led inexorably to the next. He wanted to be both Watson and Holmes to Conan Doyle, to be his narrator and his detective. Yet he knew the words of Holmes: “Data! Data! Data! I can’t make bricks without clay.” And the only way to succeed, he realized, was to track down the lost archive.

  “Murder,” Owen Dudley Edwards, a highly regarded Conan Doyle scholar, said. “I fear that is what the preponderance of the evidence points to.”

  I had called him in Scotland, after Gibson informed me that Edwards was pursuing an informal investigation into Green’s death. Edwards had worked with Green to stop the auction, which took place, in spite of the uproar, almost two months after Green’s body was found. Edwards said of his friend, “I think he knew too much about the archive.”

  A few days later, I flew to Edinburgh, where Edwards promised to share with me his findings. We had arranged to meet at a hotel on the edge of the old city. It was on a hill studded with medieval castles and covered in a thin mist, not far from where Conan Doyle had studied medicine under Dr. Joseph Bell, one of the models for Sherlock Holmes. (Once, during a class, Bell held up a glass vial. “This, gentlemen, contains a most potent drug,” he said. “It is extremely bitter to the taste.” To the class’s astonishment, he touched the amber liquid, lifted a finger to his mouth, and licked it. He then declared, “Not one of you has developed his power of perception … while I placed my index finger in the awful brew, it was my middle finger—aye—which somehow found its way into my mouth.”)

  Edwards greeted me in the hotel lobby. He is a short, pear-shaped man with wild gray sideburns and an even wilder gray beard. A history professor at the University of Edinburgh, he wore a rumpled tweed coat over a V-neck sweater, and carried a knapsack on his shoulder.

  We sat down at the restaurant, and I waited as he rummaged through the books in his bag. Edwards, who has written numerous books, including “The Quest for Sherlock Holmes,” an acclaimed account of Conan Doyle’s early life, began pulling out copies of Green’s edited collections. Green, he said, was “the world’s greatest Conan Doyle expert. I have the authority to say it. Richard ultimately became the greatest of us all. That is a firm and definite statement of someone who knows.”

  As he spoke, he tended to pull his chin in toward his chest, so that his beard fanned out. He told me that he had met Green in 1981, while researching his book on Conan Doyle. At the time, Green was still working on his bibliography with Gibson; even so, he had shared all his data with Edwards. “That was the kind of scholar he was,” he said.

  To Edwards, Green’s death was even more baffling than the crimes in a Holmes story. He picked up one of the Conan Doyle collections and read aloud from “A Case of Identity,” in the cool, ironical voice of Holmes:

  Life is infinitely stranger than anything which the mind of man could invent. We would not dare to conceive the things which are really mere commonplaces of existence. If we could fly out of that window hand in hand, hover over this great city, gently remove the roofs, and peep in at the queer things which are going on, the strange coincidences, the plannings, the cross-purposes, the wonderful chains of events, working through generations, and leading to the most outré results, it would make all fiction with its conventionalities and foreseen conclusions most stale and unprofitable.

  After Edwards closed the book, he explained that he had spoken frequently with Green about the Christie’s sale. “Our lives have been dominated by the fact that Conan Doyle had five children, three of whom became his literary heirs,” Edwards said. “The two boys were playboys. One of them, Denis, was, I gather, utterly selfish. The other one, Adrian, was a repulsive crook. And then there was an absolutely wonderful daughter.”

  Green, he said, had become so close to the daughter, Dame Jean, that he came to be known as the son she never had, even though in the past Conan Doyle’s children had typically had fractious relationships with their father’s biographers. In the early nineteen-forties, for example, Adrian and Denis had cooperated with Hesketh Pearson on “Conan Doyle: His Life and Art,” but when the book came out and portrayed Conan Doyle as “the man in the street,” a phrase Conan Doyle himself had used, Adrian rushed into print his own biography, “The True Conan Doyle,” and Denis allegedly challenged Pearson to a duel. Dame Jean had subsequently taken it upon herself to guard her father’s legacy against scholars who might present him in too stark a light. Yet she confided in Green, who had tried to balance his veneration of his subject with a commitment to the truth.

  Edwards said that Dame Jean not only gave Green a glimpse of the treasured archive; she also asked for his help in transferring various papers to her solicitor’s office. “Richard told me that he had physically moved them,” Edwards said. “So his knowledge was really quite dangerous.”

  He claimed that Green was “the biggest figure standing in the way” of the Christie’s auction, since he had seen some of the papers and could testify that Dame Jean had intended to donate them to the British Library. Soon after the sale was announced, Edwards said, he and Green had learned that Charles Foley, Sir Arthur’s great-nephew, and two of Foley’s cousins were behind the sale. But neither he nor Green could understand how these distant heirs had legally obtained control of the archive. “All we were clear about was that there was a scam and that, clearly, someone was robbing stuff that should go to the British Library,” Edwards said. He added, “This was not a hypothesis—it was quite certain in our own minds.”

  Edwards also had little doubt that somebody had murdered his friend. He noted the circumstantial details—Green’s mention of threats to his life, his reference to the American who was “trying to bring him down.” Some observers, he said, had speculated that Green’s death might have been the result of autoerotic asphyxiation, but he told me that there were no signs that Green was engaged in sexual activity at the time. He added that garroting is typically a brutal method of execution—“a method of murder which a skilled professional would use.” What’s more, Green had no known history of depression. Edwards pointed out that Green, on the day before he died, had made plans with another friend for a holiday in Italy the following week. Moreover, he said, if Green had killed himself, there surely would have been a suicide note; it was inconceivable that a man who kept notes on everything would not have left one.

  “There are other things,” Edwards continued. “He was garroted with a bootlace, yet he always wore slip-on shoes.” And Edwards found meaning in seemingly insignificant details, the kind that Holmes might note—particularly, the partially empty bottle of gin by his bed. To Edwards, this was a clear sign of the presence of a stranger, since Green, an oenophile, had drunk wine at supper that evening, and would never have followed wine with gin.

  “Whoever did this is still at large,” Edwards said. He put a hand on my shoulder. “Please be careful. I don’t want to see you garroted, like poor Richard.” Before we parted, he told me one more thing—he knew who the American was.

  The American, who asked that I not use his name, lives in Washington, D.C. After I tracked him down, he agreed to meet me at Timberlake’s pub near Dupont Circle. I found him sitting at the bar, sipping red wine. Though he was slumped over, he looked strikingly tall, with a hawkish nose and a thinning ring of gray hair. He appeared to be in his fifties and wore blue jeans and a button-down white shirt, with a fountain pen sticking out of the front pocket, like a professor.

  After pausing a moment to deduce who I was, he stood and led me to a table in the back of the room, which was filled with smoke and sounds from a jukebox. We ordered dinner, and he proceeded to tell me what Edwards had loosely sketched out: that he was a longtime member of the Baker Street Irregulars and had, for many years, helped to represent Conan Doyle’s literary estate in America. It is his main job, though, that has given him a slightly menacing air—at least in the minds of Green’s friends. He works for the Pentagon in a high-ranking post that deals with clandestine operations. (“One of Donald Rumsfeld’s pals,” as Edwards described him.)

  The American said that after he received a Ph.D. in international relations, in 1970, and became an expert on the Cold War and nuclear doctrine, he was drawn into the Sherlockian games and their pursuit of immaculate logic. “I’ve always kept the two worlds separate,” he told me at one point. “I don’t think a lot of people at the Pentagon would understand my fascination with a literary character.” He met Green through the Sherlockian community, he said. As members of the Baker Street Irregulars, both had been given official titles from the Holmes stories. The American was “Rodger Prescott of evil memory,” after the American counterfeiter in “The Adventure of the Three Garridebs.” Green was known as “The Three Gables,” after the villa in “The Adventure of the Three Gables,” which is ransacked by burglars in search of a scandalous biographical manuscript.

  In the mid-nineteen-eighties, the American said, he and Green had collaborated on several projects. As the editor of a collection of essays on Conan Doyle, he had asked Green, whom he considered “the single most knowledgeable living person on Conan Doyle,” to write the crucial chapter on the author’s 1924 memoir. “My relationship with Richard was always productive,” he recalled. Then, in the early nineteen-nineties, he said, they had had a falling out—a result, he added, of a startling rupture in Green’s relationship with Dame Jean.

  “Richard had gotten very close to Dame Jean, and was getting all sorts of family photographs, having represented himself as a great admirer of Conan Doyle,” he said. “And then she saw something in print by him and suddenly realized that he had been representing his views very differently, and that was kind of the end of it.”

  The American insisted that he couldn’t remember what Green had written that upset her. But Edwards, and others in Holmesian circles, said that the reason nobody could recall a specific offense was that Green’s essays had never been particularly inflammatory. According to R. Dixon Smith, a friend of Green’s and a longtime Conan Doyle book dealer, the American played on Dame Jean’s sensitivities about her father’s reputation and seized upon some of Green’s candid words, which had never upset her before, then “twisted” them like “a screw.” Edwards said of the American, “I think he did everything he possibly could to injure Richard. He drove a wedge between Richard and Dame Jean Conan Doyle.” After Dame Jean cast Green out, Edwards and others noted, the American grew closer to her. Edwards told me that Green never got over the quarrel with Dame Jean. “He used to look at me like his heart was breaking,” he said.

  When I pressed the American further about the incident, he said simply, “Because I was Jean’s representative, I got caught in the middle of it.” Soon after, he said, “the good feeling and cooperation by Green toward me ended.” At Sherlockian events, he said, they continued to see each other, but Green, always reserved, would often avoid him.

  Smith had told me that in Green’s final months he often seemed “preoccupied” with the American. “He kept wondering, What’s he gonna do next?” During the last week of his life, Green told several friends that the American was working to defeat his crusade against the auction, and he expressed fear that his rival might try to damage his scholarly reputation. On March 24th, two days before he died, Green learned that the American was in London and was planning to attend a meeting that evening of the Sherlock Holmes Society. A friend said that Green called him and exclaimed, “I don’t want to see him! I don’t want to go.” Green backed out of the meeting at the last minute. The friend said of the American, “I think he scared Richard.”

  As I mentioned some of the allegations of Green’s friends, the American unfolded his napkin and touched the corners of his mouth. He explained that during his visit to London he had offered counsel to Charles Foley—whom he now served as a literary representative, as he had for Dame Jean—and discussed the sale of the archive at Christie’s. But the American emphasized that he had not seen or spoken to Green for more than a year. On the night that Green died, he revealed with some embarrassment, he was walking through London with his wife on a group tour of Jack the Ripper’s crime scenes. He said that he had learned only recently that Green had become fixated on him before his death, and he noted that some Sherlockians blurred the line between fandom and fanaticism. “It was because of the way people felt about the character,” he said. Holmes was a sort of “vampire-like creature,” he said; he consumed some people.

  The waiter had served our meals, and the American paused to take a bite of steak and onion rings. He then explained that Conan Doyle had felt oppressed by his creation. Though the stories had made him the highest-paid author of his day, Conan Doyle wearied of constantly “inventing problems and building up chains of inductive reason,” as he once said bitterly. In the stories, Holmes himself seems overwhelmed by his task, going days without sleep, and, after solving a case, often shooting up cocaine (“a seven-percent solution”) in order to spell the subsequent drain and boredom. But, for Conan Doyle, there seemed to be no similar release, and he confided to one friend that “Holmes is becoming such a burden to me that it makes my life unendurable.”

  The very qualities that had made Holmes invincible—“his character admits of no light or shade,” as Conan Doyle put it—eventually made him intolerable. Moreover, Conan Doyle feared that the detective stories eclipsed what he called his “more serious literary work.” He had spent years researching several historical novels, which, he was convinced, would earn him a place in the pantheon of writers. In 1891, after he finished “The White Company,” which was set in the Middle Ages and based on tales of “gallant, pious knights,” he proclaimed, “Well, I’ll never beat that.” The book was popular in its day, but it was soon obscured by the shadow of Holmes, as were his other novels, with their comparatively stilted, lifeless prose. After Conan Doyle completed the domestic novel “A Duet with an Occasional Chorus,” in 1899, Andrew Lang, a well-known critic who had helped publish one of his previous books, summed up the sentiment of most readers: “It may be a vulgar taste, but we decidedly prefer the adventures of Dr. Watson with Sherlock Holmes.”

  Conan Doyle was increasingly dismayed by the great paradox of his success: the more real Holmes became in the minds of readers, the less the author seemed to exist. Finally, Conan Doyle felt that he had no choice. As the American put it, “He had to kill Sherlock Holmes.” Conan Doyle knew that the death had to be spectacular. “A man like that mustn’t die of a pin-prick or influenza,” he told a close friend. “His end must be violent and intensely dramatic.” For months, he tried to imagine the perfect murder. Then, in December, 1893, six years after he gave birth to Holmes, Conan Doyle published “The Final Problem.” The story breaks from the established formula: there is no puzzle to be solved, no dazzling display of deductive genius. And this time Holmes is the one pursued. He is being chased by Professor Moriarty, “the Napoleon of crime,” who is “the organizer of half that is evil and of nearly all that is undetected in this great city” of London. Moriarty is the first true counterpart to Holmes, a mathematician who is, as Holmes informs Watson, “a genius, a philosopher, an abstract thinker.” Tall and ascetic-looking, he even physically resembles Holmes.

  What is most striking about the story, though, is that the two great logicians have descended into illogic—they are paranoid, and consumed only with each other. At one point, Moriarty tells Holmes, “This is not danger.… It is inevitable destruction.” Finally, the two converge on a cliff overlooking Reichenbach Falls, in Switzerland. As Watson later deduces from evidence at the scene, Holmes and Moriarty struggled by the edge of the precipice before plunging to their deaths. After finishing the story, Conan Doyle wrote in his diary, with apparent delight, “Killed Holmes.”

  As the American spoke of these details, he seemed stunned that Conan Doyle had gone through with such an extraordinary act. Still, he pointed out, Conan Doyle could not escape from his creation. In England, men reportedly wore black armbands in mourning. In America, clubs devoted to the cause “Let’s Keep Holmes Alive” were formed. Though Conan Doyle insisted that Holmes’s death was “justifiable homicide,” readers denounced him as a brute and demanded that he resuscitate their hero; after all, no one had actually seen him go over the cliff. As Green wrote in a 1983 essay, “If ever a murderer was to be haunted by the man he had killed and to be forced to atone for his act, it was the creator, turned destroyer, of Sherlock Holmes.” In 1901, under increasing pressure, Conan Doyle released “The Hound of the Baskervilles,” about an ancient family curse, but the events in the story antedated Holmes’s death. Then, two years later, Conan Doyle succumbed completely, and began writing new Holmes stories, explaining, less than convincingly, in “The Adventure of the Empty House,” that Holmes had never plunged to his death but merely arranged it to look that way so he could escape from Moriarty’s gang.