The face on the WANTED poster stares at Clare O'Connor as the 7th grader enters Shrine of the Little Flower School.

Above every drinking fountain, Clare and her schoolmates see composite sketches of the kidnapper's beguilling grin. Beneath his smirk, Clare believes he is slowly grinding his teeth, the way he might have done when he killed four children about her age.

At every turn, she sees the black $50,000 REWARD sign and rereads the warnings: DON'T GO WITH STRANGERS. STAY OUT OF REACH. STAY AWAY FROM CARS.

"When I'm walking home from school and I come to the corners, I panic and think 'What if I stop walking and a car is there.' When there is I look inside to see if it is the man's face," said Clare, brushing long brown hair away from troubled blue eyes.

Stopping at corners and walking under viaducts is les frightening when Clare goes home with her friend Mary Pat Clahoun, 13. Mary lives midway between the suburban Detroit homes of the first two victims - Mark Stebbins, a lonely 12-year-old found dead in a parking lot, suffocated and sexually assaulted in February of 1976; and Jill Robinson, a 12-year-old running away from home, found on the edge of the freeway with a shotgun blast through her head last December.

That is why after basketball practice, Mary's brother Joey, 10, heads home in a group of three. The coach will not let players out of the gym alone.

If Joey is 10 minutes late, his mother, Jacqueline Calhoun, immediately panics and thinks he is victim No. 5. Mrs. Calhoun jumps to conclusions if it is a snowy day, remembering that snow may set the killer off, recalling an anonymous caller's warning to police last year: "You better hope and pray it doesn't snow again."

At dusk, Joey and his friends cannot play in the snow on their own front lawns; they cannot ride bikes to the neighborhood store where the third victim, Kristine Mihelich, 10, was kidnapped, smothered and found lying in a shroud of snow last January.

That is why after the first snowstorm this year, area schools began morning safety checks, requiring mothers to call in by 8:15 a.m. when their children will be absent that day. Even if children live across from school, some mothers drive them, walk them, whatever it takes to get them there safely.

For the third winter, Mrs. Calhoun and her neighbors are living with constant dread and with heightened awareness of what it means to lose a child.

Their children are learning early lessons about death and growing up in a cocoon. Yet children are not openly rebelling aginst almost oppressure limits on their freedom. They obey out of the real fear that they may be the killer's next victim.

Police warn some overly protective parents may be raising a generation of neurotic children, warning paranoia can be as dangerous as apathy. But staying calm is not easy:

"You'd be terrified to know the staggering number of psychos, schizos and oddball living in this town alone that police have checked out," said Mrs. Calhoun, shaking her head.

"Even after this killer is caught, I'll never let my guard down."

With each murder, friends have become strangers. None of the one million residents in affluent Oakland County is above suspicion from clergymen to policemen themselves. Friends and Lovers

Item: People are suspicious not even lovers are exempt. A 19-year-old woman thinks her boyfriend is the killer. She keeps bringing in evidence to police headquarters that implicates him as the kidnaper. "He has been cleared but she just won't accept that," said one task force officer. The Freindly Stranger

Nearly 13,000 tips are being checked out by police. But they do not have one solid clue to the identity of this artful kidnapper, despite exhaustive nationwide attempts to find him.

He is so sophisticated, police are not ruling out the possibility that he uses hypnosis - perhaps the way intelligent children are persuaded to climb into his car. Somehow the killer wins his victims over and before he smothers them, he cooks favorite meals and presses their clothes. For these morbid habits, police have dubbed the child killer "The Babysitter."

A new poster cautions: "Be aware and alert your child that this person could be posing in such trustworthy positions as a police officer, doctor or clergyman or even a friend of a family member. He may have changed his appearance since sketches of his face have been posted."

The prototype for the child killer's crimes is a faceless stranger. McDonald's restaurants have placemats with a warning about the stranger on them. Department stores are selling Don't Go With Stranger T-Shirts. Gas stations are passing out "Riddle of the Friendly Stranger Coloring Books."

The Stranger has invaded the world of childhood fantasy. Children worry aloud, like Mary. "What if the killer catches me? How would he get me in the car? Would I get chicken to eat, like Tim King, the fourth victim killed in March? Would the killer drop me in a ditch filled with snow? Why does he do it?"

"I've thought if he picks me up," Mary said, "I'd feel frustration because I'd get no help, even when everyone is around.

"If I am going to die, I'd rather it be fast and not be scared all those nights, hoping to get free." You Worry, You Worry

Item: Keeping track of 900 students gives Sister Patricia Marie, head sister of Shrine of the Little Flower School, plenty to worry about. "It makes you mad that just because of one sick person, all this has to be," she said.

You worry if you keep a child after school five minutes and if something happens on his way home you'd never forgive yourself."

Sister Patricia is reminded constantly that the killer is at large. Everytime a student is stopped for directions by a motorist, she will come and report the driver to her. One of her 7th grade students is so nervous that she keeps getting sick to her stomach has to be sent home. Finally the child's mother asked what was bothering her and she said tearfully, "the killer." The Daring Dreamers

Safe in their comfortable living room, Mary, Joey and their youngest brother Danny, 8, plan daring escapes like crawling out of windows when the killer is asleep. They scheme about how they'd punish the killer if they caught him:

"I'd shoot him with a machine gun," said Danny, with a wide dimpled grin.

"I'd put him in an electric chair," said Joey.

He bravely plots clever ways to trap the child killer before he kidnaps another victim this year. Joey asks why he can't be caught as easily as the villian in a Columbo television episode.

The lanky blond basketball player thinks the best way to catch the killer is to bait him out of hiding. What you would have to do, he said, is maybe get 12 patrol cars and have one at each end of six streets. Then you'd get two kids, not weaklings - but two who could walk a mild in the dark.

Each kid would start walking at an opposite end of one street. Just when the child killer was going to grab one kid - the police cars would move in and nab the killer instead.

"We wish he'd pop out, like on TV," Joey said. "Then you wouldn't have to be worried all the time about a car stopping and a man pulling you in . . ." The Living Nightmare

A few miles north of Joey's house, Tim King's schoolmates worry about whether the child killer will come around their neighborhood again. They have not forgotten how Tim was snatched at the corner drugstore three blocks from home in late March. Days later his 63-pound body was found in a shallow ditch, smothered to death, and sexually assaulted.

Neighbors of the King family openly admire their strength and say they have never stopped living. But Tim's parents are still reliving the nightmare that began when their son was kidnaped . . .

The night Tim disappeared, he was on his way to buy candy, a funny, impulsive eater, known to have Coney Islands and banana cream pie for breakfast.

His parents, Marion King and attorney Barry King would be gone just an hour, going out to witness a client signing his will.

At 5:30 p.m., the Kings left their son alone at their Cape Cod home on Yorkshire Street. Before returning, just on the spur of the moment, the Kings stopped for a hamburger, a meal they have regretted countless, sleepless nights:

"When we got home, Tim wasn't there," said Mrs. King.

"I just had a very sick feeling when he wasn't home. But I couldn't consciously conjecture what happened to him," said the frail, 98-pound woman.

Police all over the state were on their feet working 48-hour shifts, hunting for Tim's body, hoping to find him alive.

"There is the exhaustion," said Mrs. King, smoking one cigarette after another. "You just can't live with that kind of panic day after day.

"We waited six days and then we heard it," she said. "Barry heard it on the radio coming home and I saw it on television - a body had been found.

"Police Chief Tobin got our old parish priest and they came over after midnight to tell us face-to-face - It was Timmie."

Sitting in an armchair by the bay window, Barry King quietly analyzes the whole ordeal. He is a husky outdoors man beneath his gray-flannel suit and white starched collar, the kind of man accustomed to dealing with the rules of logic.

After the first 24 hours, he concluded his son would meet the same fate as the rest of the victims, unless something would intervene - and it obviously did't, King explains.

"It is all a horror-dream to me. I never for a moment thought it was any one in the neighborhood. It goes through your mind, but is never a logical thought.

"I am amazed that I do not have that sense of vengeance," King says, leaning back in his chair and closing his eyes. "But no man should be able to abuse and kill a child . . ."

King tried to go to his office the day after they found Tim. But his power of concentration was dimmed. "It is with you every day of your life," said King, his deep voice cracking.

"When Timmie was around you'd have to do a lot of listening. The changes here are very private.

"When I went to the opening baseball game this year, I said to myself, 'Last year I went with Tim and we sat right over there and a foul ball came our way and Timmie was so darn mad he didn't catch it.'

"Pretty near anywhere I go, I think these things." The Look-Alike

Two witnesses saw a dark-haired man in his late 20s driving a blue Gremlin near the spot Tim was abducted. Police have checked 1,200 blue Gremlin owners in Michigan - with no luck. They have 1,000 names to invesitgate.

A 40-year-old man recently was arrested for alleged criminal sexual conduct involving dozens of children. But his living habits are too unkempt to be the child killer, police reason. The killer is a stickler of cleanliness, often bathing his victims before they are smothered.

A well-known clergyman who lives alone and who preaches unorthox views was under police surveillance but has now been cleared.

His dark features bear a strong resemblance to sketches of the suspect.

This clergyman talked recently about his unfortunate look-alike as he stared out the window of his apartment, watching the cold winter rain fall:

"People have their imaginations," he said stoically. "I understand it; I'm not paranoic.

"If anyone makes an accusation, police have to follow up on it. Even if it's a senile old lady who calls up and says, 'I just saw that killer's picture in the paper, and he looks just like that clergyman.'

"My interview with police was routine and very discreet. It was like being stopped by a customs officer at the border. When police don't know who the killer is," said the clergyman, "they suspect everyone.

"Besides, I ended up interviewing the police, asking them what they were doing. It was all in good humor. I understand that the emotions of the people are enormous. People can't direct their anger at any one person - that is the frustration." Blankets of Snow

Hopes that the child killer would be caught before the first snow storm rose in October and then fell when forensic psychologist Bruce Danto arranged to meet a man named Allen who claimed to live the killer. But Allen has never surfaced and he has not contacted Danto again, despite pleas on local evening news programs.

Danto believes the killer acts out a death ritual and covers his victims in a blanket snow like a mother tucking a child in at night. But parents are tired of theories.

In the November elections the child killings became a political issue: one local official accusing the other of bungling the investigation, relying on phony psychologists, harboring petty jealousies and smudging valuable fingerprints.

Much of the criticism is directed at Task Force Commander Lt. Robert Robertson who heads the largest special statewide police effort of its kind in the country, financed by a $600,000 federal grant, that is fast running out.

For the past nine months, Robertson has been living in a fish bowl at headquarters in a vacant elementary school and at home where he sleeps with the police radio on his night table.

Some nights he is awakened by a news bulletin or a tipster's phone call from as far south as Georgia. Some nights he can be soothed back to sleep by his wife of 25 years. Panic and Pretense

Item: When any child is reported missing, panic sets in. In December a youngster ran away instead of going to school. For three days, he hid in the area. Police searched everywhere and his parents were beside themselves, convinced he was the killer's fifth victim. When he was found it turned out he had run away because he was angry with his mother.

Weeks later, some children reported they saw a little girl abducted. The whole task force went into high gear, only to find out the youngsters made up the whole thing up . . . The Commander

At headquarters Robertson rummages through his desk drawer for the latest reward poster. Instead he finds an old Dick Tracy comic book under his pistol:

"We've got to have humor in this place or we'll all go crazy," said the commander, crossing his arms over his barrel chest. "Besides, Tracy never had a crime he couldn't solve."

About the crime at hand, Robertson is more pessimistic. He spent thousands of man hours on that Allen letter and still doesn't know if it was for real or just a plain prank.

"We don't have one hot prime suspect," he said, shaking his head streaked with more than a few gray hairs. "We tell the truth here or we don't answer. But you just plain get tired blood.

"People call up and say, 'They caught Son of Sam. Why can't you catch that child killer?'

"I get calls from Ohio. They say they got a guy who looks like our man. He looks like nothin', I tell them. There ain't nothin' like our case, nothin'," said Robertson.

"We hand out do's and don'ts - what parents can do, what schools can do, what police can do . . .

"But if this killer wants to grab another kid tonight, he can grab one. He's just that smooth."

In the heat of emotions, Robertson tells his men they still have to be objective. They had a recent case with a homosexual priest who really looked like their man. But the guy has never been with girls and two of the victims were young girls, the commander reasoned. The suspect was stamped "Clear."

"Jesus, there are a lot of homosexuals around here," said Robertson. "One under every tree . . . "

When the commander is driving, he says he thinks over all these facts. He mulls over the facts at lunchtime when he takes an apple and diet Pepsi out of his briefcase, eating alone at his desk.

He rereads hundreds of pages of testimony in the Jill Robinson case.

And sometimes at home when he gets a little hyper, Robertson plays his guitar and sings a few songs, a country boy at heart from Cedar Springs, Mich., home of red flannel.

The Robertson goes for a little jogging. "It gives you a chance to sweat a little," he said.

"When you gasp for air - you don't have time to think."