Stefanie Rock, of Manhattan, struck and killed while running in Water Mill, police say

A Manhattan woman was fatally struck by a car on Friday morning as she ran on a road in Water Mill, Southampton Town Police said.

Stefanie Rock, 29, was running north on Deerfield Road when she was struck by a Toyota traveling south, police said in a statement. Rock was pronounced dead at the scene. The driver of the Toyota remained at the scene and was cooperative, police said. The unidentified driver was taken to Southampton Hospital for evaluation and released.

Southampton Town Police patrol officers and detectives, the Southampton Fire Department and the Southampton Volunteer Ambulance responded to the scene after a 911 caller reported the crash. The investigation is continuing.

By John Valenti

john.valenti@newsday.com

John Valenti, a Newsday reporter since 1981, has been honored nationally by the Associated Press, Society of the Silurians and National Headliner Awards for investigative, enterprise and breaking news reporting, as well as column writing. He is the author of “Swee'pea,” about New York playground basketball star Lloyd Daniels. His debut crime novel, “For Nothing Is Hidden,” rooted in 1950s Long Island, was released in October 2025.