A few years ago, Bill James was in a Boston hotel room, relaxing with a book about one of the city's most accomplished yet least admired sons: the Boston Strangler. There are numerous accounts of the killer's grisly 1960s spree—which left at least 14 women dead—and James has read a lot of them, possibly all of them. But this particular book stood out, mostly because the author's research was sloppy. James kept finding mistakes. In one case, even the location of one of the murders was wrong. "The guy really irritated me," James says.

James lives in Lawrence, Kansas, but he spends quite a bit of time in Boston, where he's worked for the Red Sox since 2002. Technically, he's the team's senior adviser of baseball operations, using his deep statistical knowledge of the game to help the Sox develop strategy and decide which players to sign. But it would be a mistake to think of James as a mere number cruncher. What he really does is study baseball—its history, its dynamics, its laws—and ask questions: What's the best way to use a relief pitcher? How important is a bunt? Usually, these are questions that have been put forth numerous times before and seemingly resolved. But James keeps asking them anyway. In the process, he has become one of the most celebrated analysts in the sport's history, with more than a dozen books to his name, many of them considered indispensable.

In addition to wondering about slugging percentages and pitching records, though, James has long been asking questions like: Why do some crimes become more famous than others? How reliable are eyewitness descriptions? Was the real Boston Strangler caught? Which is why his latest compendium of knowledge isn't about baseball; it's about murder. Called Popular Crime, it's an omnibus of serial killers, kidnappers, assassins, and the occasional terrorist. Most of James' research is drawn from his mammoth library of true-crime books. And after reading extensively about the Boston Strangler, he started to second-guess the supposed experts—the cops, the lawyers, the authors.

What if, James wondered, the police had arrested the wrong man? What if some key pattern to the murders had been overlooked? In the months after he first started thinking about that one book's errors, he repeatedly found himself running into some of the Strangler's old haunts and eventually decided to map out the crimes. In the end, James came up with his own theory as to what happened, which raises a question: Can a guy who changed the way we look at baseball transform the way we think about crime?

James has amassed an extensive library of true-crime books.

Photo: Jessica Dimmock

Even if you barely follow baseball—even if your greatest relationship to the game was, say, a childhood obsession with the 1980s Phillies, one that was cut short by an unpleasant encounter with a certain slugger who had a bowl-mullet haircut and a gambling problem—well, even then, you've probably heard of Bill James. He's appeared on The Simpsons and 60 Minutes and played a prominent role in the Michael Lewis best-seller Moneyball. His fan base has included everyone from the late Norman Mailer to New York Times numbers whiz Nate Silver.

James' wise-beard status can be traced to a series of self-published books he wrote in the late '70s while working at a Kansas pork-and-beans factory. Each carried the name Baseball Abstract and contained a mix of dust-dry stats and nimble prose that James used to debunk some of the sport's most deeply held beliefs. Every volume was a synaptic strand of heresy, laying out one controversial idea after another: Sacrifice bunts are often counterproductive; saving relief pitchers for the last inning is a waste; a player's offensive strength can be measured not by batting average but by something called Runs Created, a complex formula that looks like it belongs on the back of an algebra flash card. James eventually dubbed his DIY science Sabermetrics (after , a private organization that tracks baseball stats), and while some fans embraced it right away, others viewed him as a meddling nerd.

"He challenged a lot of received wisdom," says Daniel Okrent, founder of rotisserie baseball, who wrote a profile on James for Sports Illustrated that appeared in May 1981 (the piece was so contentious, the magazine held it for a year). "There was resistance among the baseball establishment. I remember manager Sparky Anderson saying, 'What do I care about some little guy with glasses and an adding machine?' And first of all, Bill's twice the size of Sparky. But you heard a great deal of that kind of thing."

James approached baseball with the wide-eyed vigor of a fan and the clear-eyed rigor of a logician. In 1982, he wrote his own article for Sports Illustrated, challenging the value of stolen bases. Titled "So What's All the Fuss?" the piece put forth the notion that stolen bases are "trendy trinkets" that don't help teams win games—a conclusion James drew after exploring an exhausting number of questions. He began with a broad query: Do base-stealing teams win? From there, he conducted an inquest of all the data he could get: How many bases are stolen in wins, and how many are stolen in losses? If a runner steals second, what are the odds he'll end up scoring a run? How often does a base-stealer lead the league in runs scored? "I try to take large, general questions that are difficult to resolve and break them down into small, very specific questions that have clear answers," James says.

The manuscript for James' addition to the true-crime genre, Popular Crime, runs 685 pages.

Photo: Jessica Dimmock

Eventually, even James' most outlandish ideas were recognized as valid. By the '90s, he was no longer an outsider; his ideas had begun to reshape the game, and he'd started working with agents, helping them determine a player's value when contracts came up. Plus, he continued to write on baseball, sometimes even going back to reexamine his own ideas, correcting flaws he had missed the first time around. "There's so much going on in that head," Okrent says. "And he guards it carefully, until he either gets to know you very well or he's prepared to write about it." Which is why many of his fans were surprised to find out that James' next book would focus not on baseball but instead on a pastime that's steeped even deeper in American culture and followed just as passionately.

James can't remember the first crime that got his attention, but growing up in Kansas in the '50s and '60s, he had plenty to choose from: There was Lowell Lee Andrews, the University of Kansas student who came home for the holidays, had supper with his family, and then inexplicably murdered them all. Then there was the 1959 slaying of the Clutter family, a massacre documented by Truman Capote's In Cold Blood. (Capote worked on parts of the book in a hotel near James' house.) For a kid from Mayetta—a town James describes as the middle of nowhere—the crime stories in the morning paper provided a glimpse of what life was like elsewhere. "That's how I learned about the world," he tells me on a gray-lit, slush-steeped winter morning in Lawrence, Kansas. "I read the sports page, the crime stories, and Dear Abby." We're in his home library, walled in by books and guarded by rows of busts that depict everyone from Groucho Marx to Abraham Lincoln; there's even a bobblehead of James himself, and while it doesn't quite nail his height and softness, it gets his black-gray beard just right. "In a crime story," James says, "the details become tremendously important—where the staircase was in relation to the bed, for example. This is what drew me in."

James began reading every true-crime story he could get his hands on. Though he'd occasionally get strange reactions when discussing his passion for books with titles like The Rabbi and the Hit Man and The Killing of Bonnie Garland, James believed crime was just as valid a subject as baseball. "The fact that it's kind of creepy obstructs that it's an important sociological phenomenon," he says. "Crime shapes how we think about the world; it shapes social decisions that we make; it shapes our base of knowledge. But we don't talk about it intelligently."

Jury trials are "like a basketball game where nobody keeps score. James' solution? Grade the Evidence on a point scale with 100 needed to convict.Throughout the '80s, while still working on his abstracts, James began writing essays on famous acts of violence. These now form the basis for Popular Crime. Some of the cases are well-known (the Zodiac Killer, Ted Bundy), others long forgotten (Erich Muenter, a Harvard lecturer who poisoned his wife, became a radical, and later tried to kill J. P. Morgan). Many of these stories are presented as quick, vivid summaries—a cozy tour of James' true-crime library. And while Popular Crime isn't quite the Sabermetrics of violence, James does apply the same methodology he uses with baseball—asking long-exhausted questions, trawling data, and digging for holes in the story. Along the way, he often comes up with a few new clues. Perhaps more important, he also develops a few Jamesian theories for fixing what he sees as our woefully misprioritized justice system.

In the book, for example, James outlines a loose mathematical system for judging a defendant's guilt or innocence. Jury trials, he says, are "like a basketball game where nobody keeps score." His solution—which he applies to the infamous 1893 trial of Lizzie Borden—is to break down each piece of evidence, judge its accuracy, and grade it using a predetermined point scale, with a total of 100 points needed to convict. Let's say a defendant had a history of violence toward the victim; if proven, it would be worth 35 points. In the case of Borden, James claims it's unclear whether she was violent—only that she despised her stepmother. So the evidence would earn only 12 points or so. (Borden's final "score," according to James, would be a mere 20—nowhere near enough to convict.)

James also posits a way to reform prisons, which he dubs "violentocracies." His proposal: smaller facilities that house no more than 24 inmates and are part of a larger, incentives-based system. At a Level 1 prison, for example, you get a lawyer, a Bible, and around-the-clock supervision; at Level 5, a cat and a coffee machine. At Level 10, you can earn a living and come and go with relative ease. The idea, James says, is not only to reduce the paranoia-fueled violence in large prisons but to encourage prisoners to work their way up the ladder.

He even gets into the minutia of police work. In reading so many crime stories over the years, James was surprised that so many weak descriptions are taken seriously, while so many good ones go unheeded. In his system, police would rank eyewitness accounts, from a few basic details about the suspect's height or race (Level 1) to IDing your neighbor as he moves a body out of the garage freezer in broad daylight (Level 6). These scales could later be applied to James' 100-point conviction system.

Bill James at home.

Photo: Jessica Dimmock

Of course, these ideas, as well-researched and cogently argued as they may be, are not necessarily workable. Take that utopian prison system, for example: What possible motive would a prisoner have for wanting to leave one of those Level 5 cells, which seem to have more amenities than some New York City apartments? James knows many of his notions are impractical and that readers will pick apart each idea. In fact, that's his hope: that people will start asking some of the same questions he does. "It's simply to get a few people to start talking," he says, "to get a few people to look at this and ask, how can I do better?"

At one point in its decades-long, off-and-on gestation, Popular Crime was going to be a book on how to catch serial killers, just because James thought it might be useful. He bought every serial-killer book he could find and systematically went over each of them with a questionnaire he'd designed, figuring out all the various ways the criminals could be apprehended. He had nearly 40 questions, ranging from "Did this person know his first victim?" to "Did this person typically get in his car and drive after committing a crime?"

James eventually dropped the idea, as the results were anticlimactic: In most cases, James found, the killer was caught not by clever police work but simply because a potential victim managed to escape. Besides, even a guy consumed with gory details has his limits. "Serial murders are just the worst stories," he says. "It can take an emotional toll on you."

Yet serial killers remain an object of fascination for James. It makes sense. After all, they tend to put up big numbers, and each crime leaves behind more data to mine, more patterns to study.

Sometimes, however, raw data isn't enough. This was especially true with the Boston Strangler, a case so perplexing that James couldn't help but do a little firsthand reporting.

And that's how James found himself on the streets of Boston, wandering around the Strangler's old killing grounds. As he explored, James noticed that several of the murders had been committed near the city's Green Line train—but the police had claimed the Strangler drove to his victims. James doesn't buy it. Why would the killer take a car to an area that was so famously hard to navigate? Wouldn't it have been easier simply to pick victims from along the Green Line, then jump back on the train after each murder? What if the Boston Strangler wasn't actually from his namesake city but from nearby Brookline?

James isn't saying he cracked the case. It's just a crazy theory.

Then again, a lot of Bill James' theories have turned out to be true. Especially the crazy ones.

Contributing editor Brian Raftery (brianraftery@gmail.com) writes about America's Funniest Home Videos in issue 19.05.