That evening a search party was assembled and Sarah's pink and white bicycle, Bible school papers and crayons were found halfway along the route. The small farming community instantly mobilised a nationwide appeal for help and information. Fifty million posters of Sarah went out, and an anonymous benefactor put up a dollars 100,000 reward for her safe return. Sarah's story appeared on several network television shows. A psychic drove all the way from Arizona, convinced that Sarah's body would be found in a ditch 30 miles from her home, but there was no sign of her.
At the beginning of this year a man in Massachusetts, arrested on charges of trying to abduct another 12-year-old girl, claimed he had murdered Sarah and buried her body on the shores of a lake in the Adirondacks near the Canadian border. In one of the worst winters for years, police dug for two months through the snow, without success.
This summer, as well as the posters there are turquoise ribbons, a sign of support for Sarah's family, tied around trees and picket fences. Sarah's father marked the anniversary of her disappearance by walking 125 miles from his home to another New York state family whose four-year-old daughter has been missing since May. At the same time the evening television news has been filled with stories of missing children across the country, prompting a renewed debate about the problem.
About 800,000 children under 18 are reported missing every year - double the number 10 years ago. Some of the increase can be attributed to better reporting of the problem, but part of the rise is certainly a result of family break-up.
Of those missing, about half are children abducted by one of the parents involved in a custody case. Most of the other half run away or are thrown out of their homes and, generally, are lost for only a short time, perhaps only a day. Some are kidnapped briefly for sexual or other criminal reasons and find their own way home. Only 200 to 300 children disappear for months, like Sarah, and are presumed to have been kidnapped and murdered.
Abduction by one parent is a peculiarly American problem. Unlike most Europeans, American families are constantly on the move. In the whirl of social changes, including the high divorce rate, some parents use children as pawns, others tend to leave children unsupervised and open to exploitation.
The view of Sergeant Raymond Pyka, of the Connecticut Missing Children Clearing House, is typical of how the authorities see the problem: 'I think society is degenerating. Kids don't communicate with their parents and the parents don't worry about their kids until something drastic happens.'
When offering solutions, people divide along traditional political lines. Conservatives stress family back-to-basics policies, they want more beat police to make neighbourhoods safer and more funds put into tracking down the abductors and locking them up. Liberals favour social welfare programmes.
The split is typified by the debate on the Crime Bill that passed through Congress last week. Liberals wanted mild government-funded preventive programmes such as 'midnight basketball' to keep youths off the streets at night; conservatives pushed for more prisons.
Because of wild claims on both sides, the missing children issue is rarely straightened out in the people's minds, says Professor David Finkelhor, of the Family Research Laboratory at the University of New Hampshire.
Professor Finkelhor directed a nationwide survey on missing children for Congress in the wake of a sudden rise in media reports about missing children during the late 1980s. He found that most of the children abducted every year in family disputes were returned, and there seems to be no pressing reason to refer these cases to the police. In any case, the children are less traumatised and better off generally if they are dealt with by a social worker.
The same goes for children who run away or are thrown out of their homes. A missing children's hotline has already shown good results in these cases. Professor Finkelhor argues that only where children are abducted by a stranger and can reasonably be classed as 'endangered' should the police be involved - and armed with tougher laws.
The huge publicity given to Sarah's case has forced the New York state legislature to strengthen laws for sex offences against children. Among the measures is one that extends to the age of 18 the time limit within which sex offences against a child can be prosecuted.
By that yardstick, the New York state police have another five years to find the person who, we must assume, foully prevented Sarah from riding her bicycle home.