Readers of true crime seek the chill of a secondhand encounter with evil, and few books deliver on this promise like Ann Rule’s “The Stranger Beside Me,” perhaps the most unnerving true-crime book ever published. Rule died this past July, at the age of eighty-three, having become a best-selling author. But, in 1968, Rule was a correspondent for True Detective magazine, writing lurid tabloid accounts of crime stories from Oregon to the Canadian border. In 1971, Rule, still churning out articles, volunteered for a suicide hotline, and found herself working alongside a personable twenty-four-year-old college student named Ted Bundy.

Rule’s schedule, by coincidence, meant spending more time with Bundy than any of the other Crisis Center volunteers. If Bundy or Rule felt that a caller was truly suicidal, they would signal the other to trace the call for emergency services. As Rule later wrote of the incongruity, “Ted Bundy took lives, he also saved lives.” Because, of course, the Ted Bundy who Rule encountered was the blandly handsome and purely sociopathic serial killer who was not content to only murder his victims but to make them suffer and degrade their remains in hauntingly inhuman ways.

A close read of “The Stranger Beside Me,” however, reveals a queasy subplot: When did Rule know that Bundy was guilty? Rule describes spending hours alone with him—before the majority of his crimes, though likely not before his earliest attempts at kidnapping. Rule warms to him, considers him a friend. Bundy tells Rule of his illegitimate birth, how his grandmother posed as his mother. He confides in her his plans to win back a former girlfriend. Bundy sends Rule a Christmas card with a synopsis of her favorite O. Henry story. The story has a reference to long hair which will come to sound sinister, since Ted’s victims uniformly had long brown hair, parted in the middle.

As recounted in “The Stranger Beside Me,” Rule was commissioned in 1974 to write a book on the unsolved murders of young women in Washington. At one point, the killer-at-large lets slip to a woman he approaches in Lake Sammamish State Park that his name is Ted. This is assumed to be a false clue. Yet Rule finds herself, momentarily, thinking of her Ted. She is rattled enough to contact a Seattle homicide detective, telling him that she has a friend who matches the description, but that the perpetrator is always said to be driving a Volkswagen, and the Ted she knows doesn’t have a car. The detective surprises her with news that Bundy owns a 1968 bronze V.W. bug, the model sought. He tells her that he’s passing Bundy’s information to the county, and, when she asks, assures her that the tip will be kept anonymous.

Rule writes of her suspicion: “I forgot about it … A lot of people drove VWs … I heard nothing more to indicate Ted Bundy was a viable suspect.” Rule was not contacted again by Bundy until September, 1975, when he seeks her help to find out why his law-school records are being subpoenaed. Rule rings the Major Crimes Unit, who tell her “he’s just one of 1,200 people being checked out, it’s a routine inquiry.”

Once Bundy has the information, he chattily informs Rule of recent developments: “I think they have some kind of a wild idea I’m connected with some cases up in Washington … Everything’s going to turn out all right. But if it doesn’t, you’ll be reading about me in the papers.” Bundy’s arrest didn’t take place until a few weeks later. It’s not until the fall of 1975, after Bundy is in custody, that Rule’s role shifts from being inadvertently involved with a serial killer to an author considering how lucrative her access could be. The cynic’s game is wondering how early she began to weigh the profitability of her connection, and how far it informed her actions. In the fall of 1975, Rule reiterates her belief in Ted’s innocence, or, at least, that she had not made up her mind. This stance, as long as she maintains it, make her actions seem more reasonable. She meets Ted for a meal just after Thanksgiving, 1975, when he is out on bail from kidnapping charges, and under constant surveillance. Nothing significant is said about the case—they talk about the Crisis Clinic, old friends, their intention to meet again.

Rule again, understandably, feels the need to justify herself: “Still, I suspended judgment. Until I had proof Ted was guilty, I would wait.” Because “The Stranger Beside Me” is such a catalogue of evil, the reader does not look for the lesser sins of the person compiling these details. But, even on first reading, these passages are jarring, a running thread of Rule absolving herself to preëmpt criticism. Rule was Bundy’s pen pal and she had a book contract, but these two facts are strenuously kept separate in the telling. Even though the book chronicles what Rule thinks of Bundy, she does not clearly present the shadow narrative of when she saw the friendship and the book coalescing, and what one would mean for the other.

While Rule demurs on how much she thought of her book during this time, Bundy, no slouch on publicity, is keen to discuss writing about the case. Writing from jail, he asks for Rule’s editorial advice, for her to be his agent, for them to collaborate, to talk percentages. Rule recalls: “I didn’t know just what it was that he intended to write, but I repeated information about the book contract I had, stressed my belief his story would have to be a part of my book, just how much I couldn’t know.” All writers are pestered for publishing advice; Ted would have had little to occupy him, and would naturally consider the value of his story. But then Rule casually rounds off this episode with this thought: “I offered to share my profits, gauged by the number of chapters he might write in his own words.” The narrative moves on.

As a reader, I was stunned by this information. By this point, Bundy had been convicted of kidnapping but hadn’t been sentenced. He would not be charged with the serial killings until the following year. Rule insists that she did not have “proof” that Bundy was guilty of any crime, and so “would wait.” But what was she thinking would be in these chapters? Was the idea of Bundy contributing to the book prompted by him, or something that Rule had previously considered? Also, “number of chapters” is telling in itself. If Rule thought that Bundy was falsely accused, or was unable to decide, or if she considered him likely to be a sideshow to the main event of capturing the killer, it would be strange to offer him as many chapters as he was inclined to write.

Rule’s ethical choices as a writer are divided into two separate dilemmas. One is faced by all true-crime authors: determining how much gore is necessary to convey the grimness of events, and how much is revelling in violence for its own sake. The second dilemma, which most true-crime writers never face, is Rule’s access to Bundy. Most authors are dependent on the richness of trial transcripts and on interviews with those around the killer, rather than interviews with the sociopath himself. If they gain access to the murderer, they do not speak to him as a friend. It’s not Rule’s fault that she happened to be granted such access, but it does mean that the moral aspect of her work is questionable.