Although the 61-year-old Vietnamese immigrant had no known link to intentionally poisoned mail, she contracted inhalation anthrax and died within days.
"This is a lady who, two weeks ago, was walking around healthy," Anna Rodriguez, 47, a neighbor at 1031 Freeman St., said Wednesday. "You know, her biggest complaint was her feet, that she had feet problems, but besides that, she was a happy woman."
Nguyen worked as a supply clerk at Manhattan Eye, Ear and Throat Hospital in New York. No one knows how she contracted anthrax. As far as anyone knows, she had no relatives. Only neighbors, who became friends.
"She stayed to herself," Rodriguez said. "She lived in a community primarily of Hispanic people, but she was from Vietnam.
"Everybody loved her dearly. She lived here over 20 years and she was part of the neighborhood. Everybody knew her, some better than others, but everybody had seen her and knew that that was Kathy. That's why we're all stunned right now."
Neighbors said Nguyen came to the United States from Vietnam in 1977 and was divorced by the time she moved into her South Bronx apartment in 1982. A son, who lived with her ex-husband, died in a car crash six years ago.
There were also vague accounts of a cousin in Seattle and a brother who lived in France. But no one saw these people. When neighbors ran into Kathy Nguyen, she was, inevitably, alone.
She seemed to adopt her neighbors as an extended family, sometimes making them meals of won ton soup and crispy duck. She gave them sweaters and watches for Christmas.
They said her life focused almost entirely on work and home, a one-bedroom apartment she kept immaculate, paying $700 a month rent and taking pride in her houseplants.
Nguyen was very self-sufficient, landlord Marie Castro said. That she called the building supervisor to take her to the hospital was surprising.
"For her to ask, she must have been very ill. She truly felt she had a very bad case of the flu."
On Wednesday, Rodriguez appeared on "Good Morning America" and asked that anyone related to her friend come forward to help prepare the grave.
By Wednesday night, no one had. Ellen Borakove, a spokeswoman for the city medical examiner's office, said Nguyen's body would be kept until someone claimed it. She also said Nguyen's death had been ruled a homicide.
If no family members come forward within a few days, the residents of 1031 Freeman St. have a plan. Rodriguez said they would pass the hat and hire a funeral director. They will do the job themselves.
The Associated Press and The New York Times contributed to this story