Presumed Innocent

Parents who opt for live-in child care must often search long and hard for the sort of dedicated young woman who favors pushing strollers over pursuing more glamorous careers or beer-swilling boyfriends. Last year William and Denise Fischer figured they had found the right nanny in Olivia Riner, a demure 20- year-old who had worked as a nurse's assistant in her native Switzerland and had come highly recommended by a referral agency. But only a few weeks after joining the Fischers, Riner was charged with an unthinkable crime: setting fire to the Fischers' Thornwood, N.Y., home and murdering the baby girl she had been hired to protect.

Although a month-long trial ended in Riner's acquittal last week, the presiding judge expressed skepticism regarding her innocence, and the case remains shrouded in mystery. "I don't start no fire," Riner repeatedly stressed in her pained English throughout the ordeal. Prosecutors never uncovered any evidence linking the au pair to the crime. Nor could they establish a motive. Yet Riner herself insisted that she and the child were alone in the house when the fire started.

That leaves wide open the question of who could possibly have entered the house unnoticed and set it ablaze. During the trial, Riner's attorney developed an unsubstantiated theory pointing the finger at a young man who dated William Fischer's older daughter. The defense claimed the boy was so distressed that the Fischers made him cut back on overnight visits once the baby was born that he devised a horrific plan of revenge. An independent investigator will re-examine the case.