The case of a lifetime is closed for Howard Wells. The reporters and the well-wishers have begun to drift away, leaving the Union County Sheriff at peace. He will try to do a little fishing when the police radio is quiet, or just sit with his wife, Wanda, and talk of anything but the murderer Susan Smith.

It bothers him a little that he told a lie to catch her, but he can live with the way it all turned out. Mrs. Smith has been sentenced to life in prison.

Still, now and then his mind drifts back to nine days last autumn, and he thinks how it might have gone if he had been clumsy, if he had mishandled it. It leaves him a little cold.

For those nine days -- from Mrs. Smith's drowning of her two little boys on Oct. 25 until she finally confessed on Nov. 3 -- he handled her like a piece of glass, afraid her brittle psyche would shatter and leave him with the jagged edges of a case that might go unsolved for weeks, months or forever.

"Susan was all we had," Sheriff Wells said, sitting in his living room the other day with a sweating glass of ice tea in his hand. If he had lost her to suicide, or to madness, because he had pushed too hard, there would have been nowhere else to turn. There had been no accomplices, no confidants, no paper trails.

The manhunt for the fictitious young black man she had accused of taking her children in a carjacking would have continued. The bodies of the boys would have continued to rest at the bottom of nearby John D. Long Lake, under 18 feet of water. The people of the county would have been left to wonder, blame and hate, divided by race and opinion over what truly happened the night she gave her babies to the lake.

Even if the car had been found, it would have yielded no proof, no clues, that everything had not happened just as she said, Mr. Wells continued. He would have been left not only with the unsolved crime but also with the burden of having driven a distraught and -- for all anyone would know -- innocent woman to suicide at the age of 23.

Mr. Wells says he has no doubt that he and other investigators walked a tightrope with Mrs. Smith's mental state and that as the inquiry closed around her, she planned to kill herself. For nine days she lived in a hell of her own making, surrounded by weeping, doting relatives she had betrayed in the worst way. "She had no one to turn to," he said.

So although he was her hunter, he also became the person she could lean on, rely on, trust. But unlike Mrs. Smith, he had no way of knowing that the boys were already dead, had no way of knowing that they were not locked in a car or a closet, freezing, starving.

Someday the Smith case will be in law-enforcement textbooks. The Federal Bureau of Investigation has already asked Mr. Wells to put down in writing the procedures he used in the case, as well as any useful anecdotes from it.

But the story of how he, with the help of others, was able to bring the investigation to a close in little more than a week begins not with anything he did but with who he is.

Mr. Wells, 43, is the antithesis of the redneck Southern sheriff. He has deer heads mounted on his wall but finished at the top of his class in the F.B.I. Academy's training course. He collects guns but quotes Supreme Court decisions off the top of his head.

"I'm not a smart fellow," he said. But tell that to the people who work for him and around him, and they just roll their eyes. When the attention of the nation turned to Union in those nine days last fall, and in much of the nine months since, "we were lucky he was here," said Hugh Munn, a spokesman for the State Department of Law Enforcement.

People in the county say they like him because he is one of them. He knows what it feels like to work eight hours a day in the nerve-straining clatter and roar of the textile mills that dominate Union's economy: after high school, he worked blue-collar jobs until he was hired by the town's police force at the age of 23.

He went on to be a deputy in the county Sheriff's Department. Then, for several years, he stalked poachers and drug peddlers as an agent with the State Wildlife and Marine Resources Division.

When his brother-in-law quit as Sheriff in 1992, Mr. Wells himself ran, as a 10-to-1 underdog. He promised not to operate under a good ol' boy system of favors gained and owed, and white voters and black voters liked his plain-spokenness and the fact that he was neither backslapper nor backscratcher.

He won, by just 10 votes.

His mother, Julia Mae, was then in the hospital dying of cancer. She had lain there unmoving for hours but opened her eyes when he walked in after the election.

"Who won?" she asked.

His father, John, has Lou Gehrig's disease, and every day Mr. Wells goes by to care for him. The Sheriff went without sleep when the Susan Smith saga began on Oct. 25 but did not skip his visits to his father.

The Wellses have no children. Wanda suffered a miscarriage a few years ago, so they have become godparents to children of friends and neighbors. The Smith case pitted a man who wants children against a woman who threw hers away.

His investigation had to take two tracks. One, using hundreds of volunteers and a national crime computer web, operated on the theory that Mrs. Smith was telling the truth. The other, the one that would build a bond between a weeping mother and a doubting Sheriff, focused on her.

Mr. Wells says Mrs. Smith never imagined, would never have believed, that the disappearance of her children would bring in the F.B.I., the state police, national news organizations. He thinks that when she concocted her story, she believed that the loss of the boys would pass like any other local crime.

Like other investigators, he was suspicious of her early on. As he talked to her only minutes after she had reported her children missing, he asked her whether the carjacker had done anything to her sexually. She smiled.

It would be months before the comprehensive history of her troubled life, of suicide attempts, sexual molestation, deep depression and affairs with married men, including her own stepfather, became known. But as bits and pieces of it fell from her lips during questioning, and as cracks appeared in her already unstable mental state, Mr. Wells began to realize that Mrs. Smith, and the case, could come apart in his hands.

He had to hold her together even as he and other investigators picked her story apart, had to coax and soothe and even pray beside her, until he sensed that the time was right to confront her and try to trick her into confessing.

And he had to shield her from others, who might push too hard. Once, on Oct. 27, a state agent accused her outright. She cursed loudly and stormed away.

After that, the people who had contact with her were limited. With the assistance of Pete Logan, a warm, grandfatherly former F.B.I. agent now with the state police, Mr. Wells asked for her help in finding the boys, but did not accuse her.

The whole time, her family, her hometown and much of America were following her story, sharing her agony.

"She couldn't turn to her family, she couldn't ask for an attorney," said Mr. Wells. "She painted herself into a corner where no one could help her."

On Nov. 3, he told her, gently, that he knew she was lying, that by coincidence his own deputies had been undercover on a narcotics case at the same crossroad where she said her babies had been stolen, and at the same time, and that the officers had seen nothing. Actually there had been no such stakeout.

He prayed with her again, holding her hands, and she confessed. "I had a problem telling the lie," he said as his story unfolded in his living room the other day. "But if that's what it takes, I'd do it again."

After the confession was signed, as she sat slumped over in her chair, there was still one thing he had to know.

"Susan," he asked, "how would all this have played out?"

"I was going to write you a letter," she said, "and kill myself."

He feels sorry for her, and is disgusted by the men who used her and in their own ways contributed to the tragedy. But he is not surprised that a 23-year-old mill secretary could fool the whole nation, at least for a little while.

"Susan Smith is smart in every area," he said, "except life."