UNION, S.C. -- From the beginning, investigators thought Susan Smith was lying.
Publicly, Union County Sheriff Howard Wells launched a nationwide search for her missing children. Deputies scoured lakes and woods, counties and states -- following leads as far away as a motel in Washington state.
Privately, however, investigators spent just as much time picking apart Mrs. Smith's story: that a man stole her car and her two boys on a quiet country road.
Agents seized on inconsistencies. They gave Mrs. Smith two lie-detector tests. They searched her house. They bluffed.
Bit by bit, investigators wore Mrs. Smith down until -- nine days after she reported her children abducted -- they say she confessed to killing them.
Interviews with sources close to the investigation reveal a glimpse of what was going on behind the scenes.
Day after day, the town of Union draped itself in yellow ribbons. The American public hung on the fate of 3-year-old Michael and 14-month-old Alex Smith. People asked, how could anyone take a mother's children?
Day after day, investigators asked much smaller questions -- about a mother's story that never seemed to check out:
Mrs. Smith said a man jumped into her car while she stopped for a red light at a deserted intersection with no other cars around. But the traffic light was the kind that stays green continually unless a car coming from the cross street trips a switch and makes it turn red.
Asked where she was earlier in the evening of the alleged carjacking, Mrs. Smith said she had taken the children to Wal-Mart. No one could recall seeing the family there. She then admitted she had been lying. Why? She told investigators she thought they'd be suspicious if she told them the truth: that she had been driving around town alone with the children.
The investigation began at 9:02 p.m. Tuesday Oct. 25.
A call came in on the county's 911 emergency line. A hysterical, sobbing woman stumbled up to a home on S.C. 49, east of Union. She said a man had kidnapped her children. About 15 minutes later, Sheriff Wells was at the house, trying to calm Mrs. Smith enough to get details.
Almost immediately, the sheriff notified the South Carolina Law Enforcement Division (SLED).
The agency put out a nationwide alert for Mrs. Smith's burgundy 1990 Mazda Protege. They sent out a description of the man Mrs. Smith said kidnapped her boys.
Investigators didn't think her story fit the profile of a carjacking.
They knew that typical carjackers only want transportation and ditch the car as soon as possible. They almost never take hostages.
In questioning Mrs. Smith, investigators began to notice a disturbing pattern.
Whenever they checked her story and found an inconsistency, she would come up with an explanation that would be harder to verify.
On two lie-detector tests given days apart, Mrs. Smith each time answered several questions in a way that made investigators think she wasn't telling the truth.
Investigators focused on every aspect of Mrs. Smith's life.
The 23-year-old secretary had filed for divorce in September. And, they learned, she had only days before broken up with a boyfriend, Tom Findlay, a 27-year-old Auburn University graduate who worked as graphic arts manager.
A friend of Mrs. Smith's told investigators about a letter Mr. Findlay had sent Mrs. Smith. It said that although Mr. Findlay wanted to be with her, he wasn't ready to be a father.
The letter established a possible motive. And officials believed she would have had to leave the car within walking distance of the house where she went for help.
From that point on, the real search concentrated within a 2-mile radius of John D. Long Lake, a popular fishing and picnicking spot only a few hundred yards from the house.
Twice, state divers searched the waters near a sloping concrete boat ramp, finding nothing.
L Meanwhile, Mrs. Smith kept coming up with new explanations.
On Thursday, investigators questioned her again.
Sources wouldn't say what happened, only that investigators approached her with a ploy, received the reaction they wanted, and sent Sheriff Wells in to speak to her with a carefully scripted approach. By 3 p.m., investigators had a confession. Three hours later, divers using floodlights located the car, upside down in deep water about 100 feet from the boat ramp.