On the fifth day after the murder, the mourners of Shannon McMillan parked under a cloudless Virginia sky and walked toward the funeral chapel. They moved slowly and spoke in grim tones about the ugliness of what had happened, and the irony of it.

The death notice published that week had set out the cold essentials: "McMillan, Shannon Anne, suddenly on Sunday, October 4, 1987, at her residence in Silver Spring . . . . " By then, however, most of those filing into the Money & King Vienna Funeral Home knew more of the truth: Shannon, 22, an attractive but troubled woman who had passed through a succession of relationships with men, had been sexually assaulted in her new apartment and stabbed so many times that her wounds were difficult to count.

In the chapel, as mourners stepped forward to kneel in prayer before a crucifix, some were unaware of a discreetly placed video camera that peered out from a slight part in the drapes behind Shannon's coffin. Montgomery County police, with her mother's approval, were recording the movements and expressions of friends and family -- on the slim chance it would provide a clue to her killer.

Two detectives, leaving an unmarked van, followed the mourners into the chapel and among them sat on polished oak pews. They spoke to no one, but watched for strangers, listened to whispers, and studied each face for a sign of guilt, or worry, or feigned grief.

For days and nights before, a squad of Montgomery detectives had scratched for leads, a futile search that had begun the moment her latest boyfriend called at 10:30 a.m. on Monday, Oct. 5. He said he had just opened the door to Shannon's garden apartment at the new Hampton Point North complex in the county's Colesville section, finding her seminude body sprawled in the living room.

In the days and nights since, investigators said, they have interviewed nearly 100 people who knew Shannon, yet still have no suspect. The investigative file at the Wheaton-Glenmont police district has grown to fill a cardboard box about the size of an orange crate. Nearly 20 officers were assigned to the case in the week that ended with Shannon's funeral. Today there are two.

What has emerged from the investigation is a portrait of the victim: a young secretary whose seemingly carefree life style masked the pain of childhood trouble -- the divorce of her adoptive parents, her family's frequent moves, an estrangement from her adoptive mother, her lack of friends and a brief commitment to a psychiatric hospital.

As an adult, Shannon looked mostly to men for the closeness and stability she had missed as a youngster, according to those who knew her. "I took care of the girl almost like it was my daughter," investigators quoted one boyfriend as saying. Shannon also developed a need to indulge herself -- with a large wardrobe of stylish clothes that her girlfriends coveted, and a Nissan 380-ZX sports car that cost nearly the equivalent of her year's salary as a secretary at the National-American Wholesale Grocers Association in Falls Church.

"I guess basically she was just a young girl out looking for more than she had in life," said Detective James Drewry. "She was looking for something better."

"She wasn't a 'party girl,' " said Sgt. Gary Smith, offering an assessment shared by Shannon's friends. They described her as fond of fishing at the seashore and lying in the sun, for example, or bowling and pizza, or Trivial Pursuit on a living room rug.

When she went to bars, which was not often, she did not go alone, and rarely stayed late, her friends said. Whether she changed that habit on the last night of her life, investigators are not sure. But they have focused much of their attention on that question.

In recent interviews, Frank and Patricia McMillan recalled the period in which they both wanted a baby. After marrying in 1960, the young Air Force officer and his wife tried to conceive one, without success. Frank McMillan was stationed near San Francisco when they decided to adopt. The couple brought home a child who had entered the world just three weeks before, on Sept. 3, 1965.

They named her Shannon, for the river in Ireland.

Before she turned 7, her father's military career took the family from California to Alaska to Nebraska to Alabama. Patricia McMillan finally gave birth -- to Shannon's sister Adrienne and brother Edward.

But when Shannon was 9, her parents separated, as Frank McMillan was preparing to leave for a new post in Thailand. "Shannon loved her dad a lot," said one friend. "She told me she threw her arms around his legs and wouldn't let go of him."

Shannon's mother moved to Fairfax and remarried in 1976, settling in a comfortable town house in a middle-class neighborhood on Ellenwood Drive. Shannon was only 11, but by then, she and her mother had become alienated. Her mother, in an interview, would not elaborate on the relationship.

Shannon took every chance to escape home, according to a longtime friend, Denise Campbell, recalling Shannon as a schoolgirl. Shannon occasionally joined Campbell's family for long summer weekends at a cabin in West Virginia, and delighted in catching fireflies at dusk by the Shenandoah River.

If life at home was unhappy, life outside could also be cruel. Campbell, who now lives in Kentucky, had become Shannon's only playmate when the new girl moved to Fairfax. Although a friendly child, Shannon seldom hesitated to bluntly speak her mind, Campbell said. The other neighborhood children never accepted Shannon, and ridiculed Campbell for playing with her. Campbell recalled a group of them once cornering Shannon at a construction site after school, taunting her and pelting her with gravel.

"I get so sad when I think about it now," said Campbell's mother, Elise Patak, who encouraged her daughter to stick by Shannon. "The girl didn't fit in at home or with friends or anyplace. Nowhere."

As Shannon started her freshman year at Oakton High School in 1979, the difficult road continued. Her mother and stepfather separated in November. Four months later, her mother said, Shannon was committed to the Psychiatric Institute of Washington, and remained a patient into the summer of 1980. She wrote plaintive letters to her best friend, Denise.

"I know one thing," Campbell said. "Shannon didn't do drugs."

While Shannon was at the institute, her mother asked the Fairfax County Circuit Court to shift custody of the three children to their father, Frank. They joined him in Alabama, where he was stationed, and within months the Air Force packed them all off to Texas. Shannon was 16.

Two summers later, fresh from a San Antonio high school, she returned to Virginia. On her own finally, a new adult, she began what friends would eventually see as an often-misguided search for love, stability and a sense of self-worth.

At times in those four years, she would find a little of each, friends said. But she was still searching when somebody killed her.

"So was happy-go-lucky," one friend remembered. "We all knew she had problems in her life, but I don't think I ever heard her complain."

A few weeks after returning from Texas in June 1983, Denise Campbell said, Shannon was introduced to David Hart, the man around whom the rest of her life would revolve. Hart was 25, an Amtrak mechanic laboring hard to buy the condominium he rented in Annandale. Shannon was still 17, a slender blond with a playful smile and no idea yet how to live beyond the moment.

She soon moved in with him, beginning what Hart confirmed in an interview was an intimate but strained relationship.

"They were just so different in so many ways," said Bambi Stiteler of Annandale, one of several friends Shannon made as she moved from one secretarial job to the next.

Hart cared about his bills, the future and Shannon. Shannon cared about Hart, but not so much about bills. She wanted people to notice her, and she began assembling a stylish wardrobe and an array of tasteful jewelry that would push her charge card balances to the ceiling. Then later, she would fall in love with a silver-blue Nissan 380-ZX.

"What she wanted, she wanted -- and she got," Stiteler said. "There was never much room for compromise."

With a maturity gap between them, Shannon and Hart would quarrel, split up, then reunite, her friends said -- only to argue again, separate, then reconcile. As Stiteler put it, "They always seemed like the type who weren't happy together, and weren't happy apart."

"I was her everything," Hart would tell detectives after Shannon's death, according to a police affidavit filed in support of a request for search warrants. "I was her family, I was her father, I was her boyfriend, I was her lover . . . . I didn't exactly write her checks up and pay her bills, but I let her slide. I took care of the girl. I took care of the girl almost like it was my daughter."

And during separations, her friends said, as Shannon inevitably gravitated toward other men, Hart would reopen his arms to her. And she would return.

"I think Shannon just wanted to be loved," one friend said. "That was the bottom line."

Shannon had trained as a hairdresser at her Texas high school and worked part time at several salons in Fairfax County in the last years of her life. She made friends that way. They would occasionally meet and style one another's hair. "She was a homebody," one friend said.

At the start of 1986, she was hired as a secretary by a grocers' trade association in Falls Church, where she met Stiteler and a few other coworkers who would become her friends.

Her new friends learned not only about Shannon's shaky relationship with Hart, then in its third year, but also about pieces of her childhood. Don DiSpirito, a former coworker from Annandale, invited her for dinner a few times. "Just being in a home made her happy," said DiSpirito, whose wife and daughter also welcomed Shannon. "She could see that fiber, that stability. It meant a whole lot to her, just being there with us."

It was through another coworker, Cindy Little of Manassas, that Shannon bought her Nissan in September 1986. Little's father had offered it for sale, asking $13,500. Shannon did not negotiate. "She didn't want to test drive it, she didn't want to look inside it," Cindy Little said. "She just wanted it."

"Everywhere we went, she drove," Stiteler said. "She just loved that car. She looked good in it. And I know Dave had to help her buy it."

Shannon stopped making loan payments on the Ford she owned at the time, her friends said. After several months, it was repossessed.

"She didn't seem to care," said Mary-Frances Grauel of Alexandria, a coworker. "She looked better in a 'Z.' That was her style."

Shannon and Hart separated for the last time on Sunday, Sept. 13, her friends said. She moved to the third-floor apartment at 3318 Parkford Manor Terrace, the new Hampton Point North complex. She paid a month's rent, $565, for three rooms and a bath.

The move by Shannon -- then a legal secretary at Reed, Smith, Shaw & McClay in McLean -- surprised some of her friends, who knew she did not enjoy being by herself. But Grauel planned to move to Hampton Point at year's end and had suggested the complex to Shannon.

She brought her purebred cocker spaniel with her. She had bought the dog for $250 months before, naming it Goldie. On its birthday, friends said, she baked brownies for it.

"I think Goldie was the only thing Shannon ever had that she knew she could always have, no matter what," Grauel said. "She loved that dog."

But Shannon soon grew lonesome in her new apartment, friends said. She called them often, inviting them to visit.

The next man she dated, detectives said, was a bartender from Annandale, Thomas Cafagna. Cafagna has cooperated with police in the investigation but has declined to comment publicly. Shannon met him in a department store a few days after moving to Maryland, detectives said. They said Cafagna told Shannon where he tended bar, and suggested she stop by some night. She did, on Sept. 22 and 25, first with Bambi Stiteler, then with another friend, Sue Gass of Arlington.

Within several days, her friends said, Shannon told them she and Cafagna had discussed living together. "She was lonely as hell," Grauel said.

Shannon cooked dinner for Cafagna at her apartment one night. They made plans to attend a Redskins game the next Sunday, Oct. 4. Cafagna told detectives he knocked on Shannon's door the morning of the game, but got no answer, and went by himself. He told them he returned to check on her the next morning and found her body.

Gass said she and Shannon spoke on the telephone at dinner time on the Saturday before the game. Shannon seemed bored. She wanted to go out for the evening, but it was raining, and Gass wanted to stay home in Virginia.

"I still don't know what she did that night," Gass said.

Neither do the police.