When William and Denise Fischer said goodbye to their 3-month-old daughter, Kristie, on the morning of December 2, 1991, they did not know it would be the last time they would see her alive. Hours later, the infant died in a fire that engulfed her family’s home in Thornwood, New York.
Authorities later alleged that the couple’s 20-year-old au pair, Olivia Riner, a Swiss national, intentionally set the fire after dousing the baby with a flammable substance. The case quickly drew widespread attention due to the shocking nature of the accusations and the circumstances surrounding the investigation.
Riner had begun working for the Fischer family just one month earlier. She had been hired through an au pair agency and arrived with strong references, including prior experience assisting a pediatrician. At the time of the fire, she spoke limited English and primarily communicated in Swiss-German.
Riner was alone in the two-story home with Kristie while William Fischer, then 48, was at his auto repair business and Denise Fischer, 39, was at work as an accountant. According to Riner, she had placed the baby in a plastic car seat in the nursery, where Kristie often slept, while she fed the family’s four cats.
Shortly after 5 p.m., Riner made two emergency calls. In the first, she reported a fire. In a second call minutes later, she urgently stated that the baby was still inside the home. Riner later told investigators she became aware of the fire only after one of the cats became agitated.
Before firefighters arrived, John P. Gallagher III, a 26-year-old auto mechanic and the boyfriend of William Fischer’s adult daughter, arrived at the home. Gallagher later testified that he took a fire extinguisher from Riner, forced open the nursery door—which he claimed was locked—and put out the flames. He said the child was already dead when he reached her.
Emergency crews arrived shortly afterward. Investigators later reported that multiple fires had been set inside the house, including one in the nursery, and said evidence of a possible accelerant was found.
Riner was questioned extensively following the incident. While Gallagher and members of the Fischer family were granted immunity in exchange for grand jury testimony, Riner was interrogated for approximately 10 hours without an attorney or interpreter present. She consistently denied setting the fire and was arrested that night on charges of arson and murder.
During questioning, Riner repeatedly maintained her innocence, stating that she did not start the fire. She was later indicted, and the case proceeded to trial.
The trial began in June 1992 and lasted approximately one month. The defense challenged the prosecution’s case, emphasizing the absence of physical evidence tying Riner to the fire or the child’s death. Prosecutors were unable to establish a clear motive.
Defense attorneys also raised concerns about the handling of the investigation, alleging that potential evidence was discarded, key items were not examined promptly, notes were not taken during witness questioning, and the crime scene was not properly secured.
The defense suggested that another individual may have been responsible, pointing to Gallagher’s relationship with the family and claiming he had been barred from staying overnight at the home after Riner was hired. Gallagher denied any involvement and was never named as a suspect.
Riner testified in her own defense, stating that she and the baby were alone in the home at the time of the fire but insisting she did not set it.
After four weeks of testimony, the jury deliberated for one day before acquitting Riner of all charges.
Outside the courthouse, Riner expressed relief while also acknowledging the tragedy, saying she was deeply saddened by the loss of the Fischer family’s child. Prosecutors later announced the case would not be reopened.
Denise Fischer, speaking publicly after the verdict, said the family remained devastated by the loss of their daughter and questioned how they would move forward.
Riner later returned to Switzerland and declined further public comment. No one was ever convicted in connection with the fire. William Fischer died in 2014.