On November 16, 1940, workers at the Consolidated Edison building on West Sixty-fourth Street in Manhattan found a homemade pipe bomb on a windowsill. Attached was a note: “Con Edison crooks, this is for you.” In September of 1941, a second bomb was found, on Nineteenth Street, just a few blocks from Con Edison’s headquarters, near Union Square. It had been left in the street, wrapped in a sock. A few months later, the New York police received a letter promising to “bring the Con Edison to justice—they will pay for their dastardly deeds.” Sixteen other letters followed, between 1941 and 1946, all written in block letters, many repeating the phrase “dastardly deeds” and all signed with the initials “F.P.” In March of 1950, a third bomb—larger and more powerful than the others—was found on the lower level of Grand Central Terminal. The next was left in a phone booth at the New York Public Library. It exploded, as did one placed in a phone booth in Grand Central. In 1954, the Mad Bomber—as he came to be known—struck four times, once in Radio City Music Hall, sending shrapnel throughout the audience. In 1955, he struck six times. The city was in an uproar. The police were getting nowhere. Late in 1956, in desperation, Inspector Howard Finney, of the New York City Police Department’s crime laboratory, and two plainclothesmen paid a visit to a psychiatrist by the name of James Brussel.

The F.B.I.’s criminal profilers try to think their way into the head of the offender. GLEN BAXTER

Brussel was a Freudian. He lived on Twelfth Street, in the West Village, and smoked a pipe. In Mexico, early in his career, he had done counter-espionage work for the F.B.I. He wrote many books, including “Instant Shrink: How to Become an Expert Psychiatrist in Ten Easy Lessons.” Finney put a stack of documents on Brussel’s desk: photographs of unexploded bombs, pictures of devastation, photostats of F.P.’s neatly lettered missives. “I didn’t miss the look in the two plainclothesmen’s eyes,” Brussel writes in his memoir, “Casebook of a Crime Psychiatrist.” “I’d seen that look before, most often in the Army, on the faces of hard, old-line, field-grade officers who were sure this newfangled psychiatry business was all nonsense.”

He began to leaf through the case materials. For sixteen years, F.P. had been fixated on the notion that Con Ed had done him some terrible injustice. Clearly, he was clinically paranoid. But paranoia takes some time to develop. F.P. had been bombing since 1940, which suggested that he was now middle-aged. Brussel looked closely at the precise lettering of F.P.’s notes to the police. This was an orderly man. He would be cautious. His work record would be exemplary. Further, the language suggested some degree of education. But there was a stilted quality to the word choice and the phrasing. Con Edison was often referred to as “the Con Edison.” And who still used the expression “dastardly deeds”? F.P. seemed to be foreign-born. Brussel looked closer at the letters, and noticed that all the letters were perfect block capitals, except the “W”s. They were misshapen, like two “U”s. To Brussel’s eye, those “W”s looked like a pair of breasts. He flipped to the crime-scene descriptions. When F.P. planted his bombs in movie theatres, he would slit the underside of the seat with a knife and stuff his explosives into the upholstery. Didn’t that seem like a symbolic act of penetrating a woman, or castrating a man—or perhaps both? F.P. had probably never progressed beyond the Oedipal stage. He was unmarried, a loner. Living with a mother figure. Brussel made another leap. F.P. was a Slav. Just as the use of a garrote would have suggested someone of Mediterranean extraction, the bomb-knife combination struck him as Eastern European. Some of the letters had been posted from Westchester County, but F.P. wouldn’t have mailed the letters from his home town. Still, a number of cities in southeastern Connecticut had a large Slavic population. And didn’t you have to pass through Westchester to get to the city from Connecticut?

Brussel waited a moment, and then, in a scene that has become legendary among criminal profilers, he made a prediction:

“One more thing.” I closed my eyes because I didn’t want to see their reaction. I saw the Bomber: impeccably neat, absolutely proper. A man who would avoid the newer styles of clothing until long custom had made them conservative. I saw him clearly—much more clearly than the facts really warranted. I knew I was letting my imagination get the better of me, but I couldn’t help it. “One more thing,” I said, my eyes closed tight. “When you catch him—and I have no doubt you will—he’ll be wearing a double-breasted suit.” “Jesus!” one of the detectives whispered. “And it will be buttoned,” I said. I opened my eyes. Finney and his men were looking at each other. “A double-breasted suit,” said the Inspector. “Yes.” “Buttoned.” “Yes.” He nodded. Without another word, they left.

A month later, George Metesky was arrested by police in connection with the New York City bombings. His name had been changed from Milauskas. He lived in Waterbury, Connecticut, with his two older sisters. He was unmarried. He was unfailingly neat. He attended Mass regularly. He had been employed by Con Edison from 1929 to 1931, and claimed to have been injured on the job. When he opened the door to the police officers, he said, “I know why you fellows are here. You think I’m the Mad Bomber.” It was midnight, and he was in his pajamas. The police asked that he get dressed. When he returned, his hair was combed into a pompadour and his shoes were newly shined. He was also wearing a double-breasted suit—buttoned.

In a new book, “Inside the Mind of BTK,” the eminent F.B.I. criminal profiler John Douglas tells the story of a serial killer who stalked the streets of Wichita, Kansas, in the nineteen-seventies and eighties. Douglas was the model for Agent Jack Crawford in “The Silence of the Lambs.” He was the protégé of the pioneering F.B.I. profiler Howard Teten, who helped establish the bureau’s Behavioral Science Unit, at Quantico, in 1972, and who was a protégé of Brussel—which, in the close-knit fraternity of profilers, is like being analyzed by the analyst who was analyzed by Freud. To Douglas, Brussel was the father of criminal profiling, and, in both style and logic, “Inside the Mind of BTK” pays homage to “Casebook of a Crime Psychiatrist” at every turn.

“BTK” stood for “Bind, Torture, Kill”—the three words that the killer used to identify himself in his taunting notes to the Wichita police. He had struck first in January, 1974, when he killed thirty-eight-year-old Joseph Otero in his home, along with his wife, Julie, their son, Joey, and their eleven-year-old daughter, who was found hanging from a water pipe in the basement with semen on her leg. The following April, he stabbed a twenty-four-year-old woman. In March, 1977, he bound and strangled another young woman, and over the next few years he committed at least four more murders. The city of Wichita was in an uproar. The police were getting nowhere. In 1984, in desperation, two police detectives from Wichita paid a visit to Quantico.

The meeting, Douglas writes, was held in a first-floor conference room of the F.B.I.’s forensic-science building. He was then nearly a decade into his career at the Behavioral Science Unit. His first two best-sellers, “Mindhunter: Inside the FBI’s Elite Serial Crime Unit,” and “Obsession: The FBI’s Legendary Profiler Probes the Psyches of Killers, Rapists, and Stalkers and Their Victims and Tells How to Fight Back,” were still in the future. Working a hundred and fifty cases a year, he was on the road constantly, but BTK was never far from his thoughts. “Some nights I’d lie awake asking myself, ‘Who the hell is this BTK?’ ” he writes. “What makes a guy like this do what he does? What makes him tick?”

Roy Hazelwood sat next to Douglas. A lean chain-smoker, Hazelwood specialized in sex crimes, and went on to write the best-sellers “Dark Dreams” and “The Evil That Men Do.” Beside Hazelwood was an ex-Air Force pilot named Ron Walker. Walker, Douglas writes, was “whip smart” and an “exceptionally quick study.” The three bureau men and the two detectives sat around a massive oak table. “The objective of our session was to keep moving forward until we ran out of juice,” Douglas writes. They would rely on the typology developed by their colleague Robert Ressler, himself the author of the true-crime best-sellers “Whoever Fights Monsters” and “I Have Lived in the Monster.” The goal was to paint a picture of the killer—of what sort of man BTK was, and what he did, and where he worked, and what he was like—and with that scene “Inside the Mind of BTK” begins.

We are now so familiar with crime stories told through the eyes of the profiler that it is easy to lose sight of how audacious the genre is. The traditional detective story begins with the body and centers on the detective’s search for the culprit. Leads are pursued. A net is cast, widening to encompass a bewilderingly diverse pool of suspects: the butler, the spurned lover, the embittered nephew, the shadowy European. That’s a Whodunit. In the profiling genre, the net is narrowed. The crime scene doesn’t initiate our search for the killer. It defines the killer for us. The profiler sifts through the case materials, looks off into the distance, and knows. “Generally, a psychiatrist can study a man and make a few reasonable predictions about what the man may do in the future—how he will react to such-and-such a stimulus, how he will behave in such-and-such a situation,” Brussel writes. “What I have done is reverse the terms of the prophecy. By studying a man’s deeds, I have deduced what kind of man he might be.” Look for a middle-aged Slav in a double-breasted suit. Profiling stories aren’t Whodunits; they’re Hedunits.

In the Hedunit, the profiler does not catch the criminal. That’s for local law enforcement. He takes the meeting. Often, he doesn’t write down his predictions. It’s up to the visiting police officers to take notes. He does not feel the need to involve himself in the subsequent investigation, or even, it turns out, to justify his predictions. Once, Douglas tells us, he drove down to the local police station and offered his services in the case of an elderly woman who had been savagely beaten and sexually assaulted. The detectives working the crime were regular cops, and Douglas was a bureau guy, so you can imagine him perched on the edge of a desk, the others pulling up chairs around him.

“ ‘Okay,’ I said to the detectives. . . . ‘Here’s what I think,’ ” Douglas begins. “It’s a sixteen- or seventeen-year-old high school kid. . . . He’ll be disheveled-looking, he’ll have scruffy hair, generally poorly groomed.” He went on: a loner, kind of weird, no girlfriend, lots of bottled-up anger. He comes to the old lady’s house. He knows she’s alone. Maybe he’s done odd jobs for her in the past. Douglas continues: