The body twisted in the wind.

It was a cold Saturday morning in December. A crew of paramedics and police officers trudged from office to office inside the dirt-blackened downtown high-rise, trying to pinpoint the location of the corpse.

A doctor in an adjacent building had seen it clearly enough from his window. Hanging out a window, at the end of a rope. But now, from inside, the cops couldn't find it. Was it . . . gone?

They kept knocking on doors: Can I look out your window, please? Just checking for something, ma'am. No sir, just routine, can I slide in behind this credenza and get a look?

And so it began, as it would end, with a mystery that wasn't a mystery.

The body was there, all right. It was just in an inconspicuous corner, at the back side of the building, hidden from view of Christmas shoppers down below.

It was dangling from an open window on the 14th floor, way up high, like a giant rag doll in a long dark overcoat. Rescue workers reached up and pulled it in out of the elements and into the warm 13th floor travel agency office. It was heavy and cold and rigid as a timber.

A stiff. This is Chicago, Capone's Chicago. Bodies turn up in unlikely places. It has always been that way, and still is. A long list of wise guys, gangbangers and hoods have ended up thrown out with yesterday's trash, buried in cornfields, rolled up in rugs and in the trunks of cars, rigor mortis and stench finding them long before the fuzz does.

But nobody could remember seeing anything like this. The dead man wore a bulletproof vest. In his pocket was some Mace and a set of brass knuckles. One end of the rope was tied to the leg of a desk. The other end was wrapped four times around the man's neck and secured with a slip knot. When the falling body ran out of slack, the rope tightened as surely as a noose.

Inside the office, the desk shuddered. . Outside, the body writhed. The neck wasn't broken. It was death by asphyxiation.

The office was so meagerly furnished you could call it naked, as if it belonged to a man who didn't care what his life looked like to others. The door was locked from the inside. On the floor was a loaded blue steel .38.

Was it murder? Suicide? Some freakish accident? It seemed like something out of a detective novel, one of those hard-boiled softcovers with tough guys with bad attitudes and purring dames with bodies that could make a man make a mistake. Raymond Chandler wrote like that, and he was great, and over the years he spawned imitators, some of whom were good and some of whom were not, some of whom struck it rich, like Elmore Leonard, and some of whom did not, like Eugene Izzi.

That was the name of the man at the end of the rope. Eugene Izzi. Friends called him Guy. It was his office. He was 43. He was dead as a doornail.

He wrote crime novels.

The only fears he would admit to were of heights and fire, and he'd beaten the heights by going down to Marseilles, Illinois, on Sundays and leaping out of airplanes with the sky divers until now he could stand on the top floor of the Sears Tower and not get sick at all, maybe just a little belly tightener. Conditioning himself. Preparing himself.

-- Eugene Izzi, "The Take"

This is a two-newspaper town. On Dec. 8, the morning after Izzi's death, both papers carried the story. They were modest stories, tucked inside, befitting the writer's modest stature. Eugene Izzi had 16 books. Some got good reviews. His writing was gritty and his plots were gripping, but his dialogue sometimes could be wooden. His stories could be excessively melodramatic. He had a weakness for cliche. He wasn't bad. He wasn't great. He was no Chandler.

Within days, the plot thickened.

The coroner reported that Izzi's body had bruises to the face, arms and thighs. Friends reported that Izzi had feared for his life. He had told them this: In researching a book, he had infiltrated a white supremacist group in Indiana, and the neo-Nazis had sniffed him out. He was tried and convicted in their kangaroo court and sentenced to die. Someone had left a threatening message on his office voice mail, he said. He played it for people: It was a woman's voice, telling him he would die by "flaming rope." He took to carrying a gun. He had moved his family into a downtown hotel, for their protection.

Now, things were smoking. Now we had Page 1 news.

Said the Sun-Times: "Novelist's hanging a whodunit."

The Tribune wrote: "Now, his death has real-life detectives scratching their heads."

It was true, they were scratching their heads -- not at the case itself, but at the calls that were flowing in from the media across the country. The phone inside the police press room at Chicago police headquarters rang. And rang. "Dateline," the New York Times, "Hard Copy," "America's Most Wanted."

Detectives Gregory Baiocchi and Michael D'Alessandro worked into the night, night after night. The narrative of the police incident report at the First Deputy's Superintendent's Office at police headquarters read: "The possibility of recent death threats being investigated. . . . Investigation continues with reports to follow."

Slowly, the police began to put the pieces together. They were the only ones, it seemed, who were not calling it a mystery. They were not calling it anything. They were savvy cops; they had seen what too much yapping to the press could do. Plus, they had one big edge over the ravening media: access to Izzi's family. Izzi's wife and children were in seclusion, talking to no one but the law, coping with their grief. They still haven't given interviews. By Day 3 or so, police had a pretty good idea what had happened to Guy Izzi. But they kept it to themselves, and the mystery continued, and grew, and took on a life of its own.

It was inevitable, really. Izzi was a mystery writer. His friends were mystery writers, professional storytellers, denizens of a world of plots and subplots and conspiracies. They trafficked in the details of violence and mayhem, and now they were being asked to make sense of the death of someone they knew.

Ask a doctor about someone's death, and you will get a medical report. Ask an insurance man, and he will tell you the beneficiaries. Ask a mystery writer, and guess what you'll get?

Tony slowly pulled the cigarette from his mouth, tossed it casually aside, put his gun away, then reached into his pocket, grasped something and then crouched down next to Zwart, careful to stay out of the way of the blood that was spurting like a fountain from Zwart's throat.

That something in his hand being a dime, which he squeezed into Zwart's palm. . . . "When you get to hell, give me a call, punk."

-- Eugene Izzi, "Tony's Justice"

It's snowing now. A blustery day. Cars hum past the narrow brick storefront in north suburban Winnetka, Ill. Inside Scotland Yard Bookstore, where Izzi had done his first book signing, there is the smell of Starbucks coffee.

It has been more than a month since Izzi's death. A Sherlock Holmes mannequin looks stoic, standing stiff-necked in the back of the room, near the Agatha Christie collection, in his bow tie, beige pants, houndstooth coat and deerstalker hat. Judy Duhl, a thin woman with cropped blond hair, sits at a varnished wood table surrounded by mysteries. She owns the place. Her lips are painted red.

This is the same table where a group of Chicago-area mystery writers who call themselves the Red Herrings meets once a month to hash out plots. A copy of one of Izzi's books, "Safe Harbour," rests on another wooden table near Sherlock. It is the store's last copy of any of Izzi's books. Duhl sold out of the rest in recent weeks, since news of Izzi's death.

"He was the most charismatic and crowd-stopping author," Duhl says. He was tall and muscular, with piercing eyes. Duhl remembers reading the manuscript for his first book, "The Take," at the behest of his publisher who was trying to drum up some publicity. Duhl couldn't put it down. The next morning, she agreed to have Izzi in.

"You could hear a pin drop. He had an audience in the palm of his hand in 20, 25 minutes. It was such a moving talk." She shivers.

"I cannot believe he wasn't murdered. I didn't know him as a suicidal person," Duhl said. "He personified the Chicago person. I'm sure anyone whose lives he touched will never believe it was anything else but murder."

She's right.

"There is no question that Guy was in the midst of investigating certain individuals at the time of his death -- that's beyond dispute," crime novelist Andrew Vachss told the Sun-Times. Vachss was one of Izzi's closest friends. "You don't wrap yourself in a Kevlar vest and carry a handgun if you're relaxed about the environment around you. He was completely sane and dedicated to his craft, which happened to mean digging up dirt."

Hugh Holton, a Chicago police lieutenant and mystery writer, is president of the Midwest chapter of the Mystery Writers of America. "He didn't strike me as the kind of guy who would commit suicide," said Holton. "If it was a fiction plot, it couldn't be any more bizarre."

"The whole thing is more mysterious with the passing of time, not less," said Izzi's New York book agent, Deborah Schneider. "I haven't a clue."

There were obvious questions: Why was he bruised, if he was a suicide? Given the length of his fall, why wasn't his neck broken? Could he have been slowly lowered down by a sadistic killer?

Then there was that tape recording, the phoned-in threat. They all had heard it. "He played that tape for just about anybody who would listen," a police source said.

Suddenly, early last month, the story of Izzi's death metamorphosed. Something happened that sealed the case as a bona fide whodunit. It became a story about a story.

A police leak to the newspapers disclosed that they had found in Izzi's pocket an 800-page manuscript, contained on three computer disks.

It was a novel that only Izzi knew he was working on. His agent didn't know. His publisher didn't know. In it, the main character, a Chicago crime writer who has infiltrated a paramilitary group, is thrown out of an office window, with a rope around his neck. But in the novel, he manages to hoist himself back up and kill his attackers. The script is identical to Izzi's death scene, down to the gun, the Mace, the bulletproof vest, even the notes in his pocket.

Had Izzi gotten lost in his own fantasy? Or was he the victim of lousy luck -- had he been trying out a scene in a new book, searching for realism, and slipped to his death?

Sitting now in the quiet bookstore, where neatly shelved novels line old-fashioned wooden book cases, Duhl wonders if the accident theory might be the answer.

"This accident sounded so like him. We who knew him felt he could try to imitate these moves in this manuscript. It's not surprising that he could have screwed up."

Duhl remembers the last time she saw Izzi, the last time he came to the bookstore, about three years ago. She remembers asking him that day why he never brought his wife and two sons there when he did book signings.

Duhl is still puzzled by his response.

"He didn't answer me," she says.

Who was Guy Izzi?

In a magazine article, he once wrote of himself: "I am a man with no casual friendships, self-contained, a man who enjoys his solitude. I believe in the family of choice. There are a half-dozen people in the world in whom I trust, and three of them have the same last name as I."

And he also once wrote this: "Those whom I love can kill me with a harsh glance, a sharply worded phrase. . . . Everyone else is just guessing, and their criticism is unimportant."

There is a paper trail, some of which Izzi left himself. A stack of old newspaper articles and magazines chronicles bits and pieces of Izzi's life. The downtown Harold Washington Library, a sprawling reddish building with 3,000-pound aluminum owls that look like gargoyles perched on its roof, holds some clues.

He grew up in the tough Hegewisch neighborhood on the city's southeast side not far from the smokestacks of sweaty steel mills, and the Indiana border. By Izzi's own account, his was a troubled childhood.

"My earliest memories of my childhood are of my father beating my mother. On more than one occasion he sent her to the hospital. His wild drunken brutality -- and the terror it instilled -- is never far from my mind." In a Chicago magazine article in 1994, he recalled the "bull-like expulsions of air that exploded from my father's nostrils as he tried to choke my mother with his belt, or as he beat her with his fists."

"Later, when I was a teenager, that horrible, brutal, high-pitched wheezing was focused on me as he stood right in my face and I shook with terror, my father screaming challenges for me to be a man and fight him, calling me a coward when I wouldn't." Izzi dropped out of school in the 10th grade, joined the Army at 17 and earned a GED. He returned home to work at U.S. Steel and tried chasing his demons with drink.

In March 1991, Izzi wrote in the Tribune: "In August of 1981 my wife had finally had enough of my drinking, of never having any money, of four of us living in two-room shacks while I sat in gin mills and poured whiskey down my throat. I would come home and give her a beating whenever she gave me a problem, which in my mind occurred when the woman pointed out my responsibilities or my shortcomings.

"The last time in my life I hit her was on Aug. 15, 1981. A parting shot to the stomach, thrown as I passed her on the way to the bedroom, to pass out after a full night of drinking. It was around 9 in the morning. When I hit her, she cried. "When I awoke, hung over, she and our two sons were gone."

Separated from his family, Izzi lived for a while in a barber shop on the South Side, sleeping on the floor of a bathroom there. It was his lowest point. Near fatal.

"I thought it was just -- everybody was out to get me," Izzi told freelance writer Paul Engleman. "I spent a lot of hours there staring at the razor blades . . . thinking, just get drunk enough to do it, show 'em all. It was at that point that I began to turn my life around." Izzi sobered up, got back together with his family, landed a construction job and started writing with a mission. He wrote seven books no one wanted before "The Take" was published by St. Martin's Press in 1987. Critics liked it.

Universal Pictures produced "The Take" for cable and also snatched up the rights for "Bad Guys," his second book. It was a start, and there was enough money to buy him a house in a south Chicago suburb. It also brought other offers, including a deal with Bantam Books.

"He was dancing with delight," Duhl recalled.

Izzi's relationship with Bantam soured. His book "Tribal Secrets" was supposed to be a blockbuster. Instead, it did poorly, and received dreadful reviews. Bantam canceled his promotional tour and heavily discounted the book on the shelves; Izzi was heartbroken.

He "basically disappeared for a while," said Sheldon McArthur, a friend who also owns a Los Angeles mystery bookstore. "I think that was probably his low point. If Izzi had contemplated suicide, that would have been the point when he would have done it, when his career was at a low ebb."

When he began writing again, it was under a pen name, Nick Gaitano. Perversely, it was under this new identity that Izzi created the character that most resembled himself. Sgt. Jake Phillips was a street-smart cop with a hard life, a soft heart, and a jaundiced view of the world.

Jake watched a bunch of tall-masted sailboats cutting the water, puzzled as to how anyone could be so content, so carefree. The people who owned those boats thought they lived in a world that was mostly safe, a world that held little personal danger to themselves. Part of Jake's job was to allow them to live through the rest of their lives suffering under that delusion.

-- Nick Gaitano, "Jaded"

Izzi had finally found himself, in print. But he was doing it furtively, under someone else's name. For some reason, he had reinvented himself.

He became more secretive, some would say imbalanced.

He worked the late shift at his Michigan Avenue office where he was halfway into a two-year lease. He was seldom seen by the scores of people who also worked in the building. No one knew what he did. Angela Issachar, 27, who works down the hall at a metal cleaning company, thought he was a private investigator because of the bulletproof vest she often saw him wearing.

Izzi took elaborate measures to protect his privacy. His phone number was unlisted, and he changed it constantly. His office door bore no signs except the shiny gold room number, 1418, not the slightest hint of who may have worked there or what he did.

If you check out the home address he gave on official documents -- 47 W. Polk St., Apt. 100 -- it leads to the city's red-brick and black historic Dearborn Train Station here in the South Loop. Inside the airy renovated marble-floored building are a few shops, a gourmet coffee cart labeled Java Express, and the Siddha Yoga Center of Chicago, but no apartments. Turns out there is something listed as "Apt. 100." It's a cozy little place called Mailboxes Etc., where Izzi rented a cubbyhole for $360 a year.

Another address on record with the Chicago Board of Elections checks out to a warehouse at the southern edge of the Loop, in a near-desolate area crawling with winos and drug addicts. No living quarters there, either.

Every day, this man with a ghastly childhood, a recovering spouse abuser and alcoholic, closeted himself in a sparsely furnished room, and, writing under a pseudonym, churned out stories about thugs and pimps and cons and cops. Killers, dopers and thieves; men who put alligator clips on other men's nipples, and hook them up to car batteries; men who stick guns in people's mouths and pull the trigger, just for the big of it.

Toward the end, the writer wore a Kevlar vest and carried a piece. The writer began telling stories of being pursued by neo-Nazis.

And, for some reason, the writer abruptly went back to his own name.

"A Matter of Honor: A Novel of Chicago," by Eugene Izzi, was the story of a racially motivated murder and the subsequent drive-by shooting of a police officer's niece. Izzi had received the galleys a week before his death.

"He was in such great spirits," said Lou Aronica, editor at Avon Books, which will publish the novel this spring. "I find it impossible to believe it was suicide. There was always a small sense in my mind that something like this could happen because Guy spent a lot of time on the streets."

In fact, Izzi had once gone undercover for several weeks as a homeless person in Chicago as research for a book he was writing about homelessness and was mugged and beaten by two hoods. He was known to disappear into the laboratory of the city's mean streets. So the idea of Izzi infiltrating a paramilitary group was not far-fetched. Neither was the idea of acting out a scene from his manuscript.

Except.

Except there were things these people did not know. Guy Izzi was clinically depressed. He had been seeing a psychiatrist. He had begun acting erratically, paranoiacally. And the stories he was telling about threats and danger -- well, they appear to have been just that -- stories. Well plotted, gritty, if excessively melodramatic. Stories.

It's snowing now. Men and women rush down a wind-whipped Michigan Avenue to get out of the cold. At the Cook County morgue, Deputy Chief Medical Examiner Mitra B. Kalelkar is wrapping up her investigation of case No. 146, DEC96. Izzi's case.

Nearly two weeks earlier, police handed over their files and all their evidence, including the manuscript found on the three disks in Izzi's pockets.

Detectives were finished questioning Izzi's mystery-writer friends, the ones who cried murder. What they found was that many hadn't seen Izzi in years, didn't know where he was living, didn't even have his telephone number. They were dated sources. Outdated.

Given the evidence, police drew the only conclusion they could logically reach about Izzi's death, hanging from a rope from a window of an empty room locked from the inside. Except they couldn't say what it was. They could only say what it wasn't. It wasn't homicide. The rest was now Kalelkar's job. As far as police were concerned, the case was closed.

And on this snowy day, 5 1/2 weeks after the grisly death, after consideration of all the evidence, all the speculation and all the so-called mystery, Kalelkar will rule the death a suicide.

He had "scripted out his death," says Kalelkar, sounding a bit tired. "The characters in the manuscript closely mirror Mr. Izzi and his friends as well as his wife and children.

"In the manuscript, he survives and everybody lives happily ever after. But that's not true in real life," she says.

It's as though Izzi was writing his story the way he wished it would end, but knew it could not. That's what writers do. They fantasize.

So, what about the mysteries?

First, the gun. No mystery there. Family members identified it as Izzi's own .38-caliber blue steel revolver, police sources said. He had often flashed it in the weeks before his death. "They're coming to get me, but don't worry. Look at this."

The bruises on his face?

No mystery. There were no defensive bruises on the body. The bruises on the face were consistent, says Kalelkar, with Izzi's head and arms repeatedly striking the side of the building. This is Chicago. The Windy City.

The bruises on the thighs, Kalelkar says, were likely caused by Izzi straddling the window sill for a while. Jumping takes courage, and sometimes you have to work yourself up to it.

Why was his neck not broken? It wouldn't have broken if he shimmied off the ledge, rather than leapt feet first. The 1929 Handbook on Hanging recommends a free-fall drop of at least 8 1/2 feet for a man of his weight, to reliably snap the spine. There was not that much rope.

And the tape recording that family and friends heard, the woman from the Indiana militia who left a threatening voice mail? Police traced the call. They do not know who the woman was, but they know she was not calling from Indiana. There is reason to suspect she may have been acting under Izzi's direction or at his behest: She was calling Izzi's office from a pay phone around the corner.

What explains Izzi's fear of death? Moving his family to a hotel? The gun and bulletproof vest? Look no further, suggests Kalelkar, than the contents of the dead man's blood. It was laced with therapeutic doses of antidepressants. Izzi was under a psychiatrist's care for serious depression. Paranoia and depression often accompany one another. All of these things suggest suicide, though they are not definitive. But there is one other piece of evidence that seems to nail it down. On the Friday night of his death, Izzi had gone to his office. He phoned one of his sons at the downtown hotel where his family was staying. He said he had been unable to get into his office because he had left his keys at home. He asked his son to meet him in the hotel lobby, with a set of keys.

The young man obeyed. There in the lobby, Izzi hugged his son and told him, "No matter what happens, I love you."

Then he went back to his office, back upstairs, to die.

Here's the thing:

Police sources say that the phone call to the hotel, the one summoning his son, was a call Izzi didn't have to make. He made it for one reason only: to say goodbye.

How do they know that? Because they traced the call. It came from inside Room 1418. Izzi's office.

CAPTION: Did he jump or was he pushed? Eugene Izzi was found dangling from a rope outside a 14th-floor window of this Chicago office building, right.

CAPTION: Book seller Judy Duhl, left, and mystery writer Hugh Holton both knew Izzi. Neither believe he was suicidal.