Eustis' son, Adam Fisher, said Thursday that she died Jan. 11 at the Beth Israel Medical Center in New York City. She was 98 and died of natural causes, Fisher said.
Eustis' "The Horizontal Man" was a crime story about a murdered English professor that won the Edgar in 1947 for best debut novel.
"Horizontal Man" will be included this fall in a Library of America anthology of 1940s-'50s crime fiction by women. Eustis also wrote "The Fool Killer" and the children's story "Mr. Death and the Redheaded Woman."