Kathleen Nguyen, 61, died on October 31, 2001, in Manhattan after arriving at Lenox Hill Hospital in sudden respiratory distress that progressed to respiratory failure. Blood cultures and laboratory testing confirmed inhalational anthrax, making her New York City’s only fatality in the 2001 anthrax outbreak.

Nguyen worked in a stockroom in the basement of Manhattan Eye, Ear and Throat Hospital. Investigators from public health and law enforcement traced her recent routines—work shifts, errands, church attendance and subway travel—interviewing co-workers, neighbors, acquaintances and her mail carrier; they searched her apartment, personal effects and workplace and sampled mailrooms, post offices and subway stations connected to her movements. Repeated cultures and environmental tests returned negative, no additional linked cases were identified, and officials were unable to establish where her exposure occurred.

In the broader Amerithrax probe, investigators later linked the mailed anthrax to material associated with U.S. Army biodefense research and announced plans to seek an indictment charging Dr. Bruce E. Ivins; Ivins died by suicide in July 2008 before charges were filed and the FBI and Justice Department closed the investigation in 2010. The official conclusion has been disputed by some scientists, and another early suspect, Steven Hatfill, was exonerated. Who remembers seeing Kathleen or noticing anything unusual in the places she frequented before October 31, 2001?