A former aide to New York governor Andrew Cuomo was among five people who died when a driver lost control and struck two other vehicles on Long Island.
Six other people were injured in the crash at around 9:30am local time on Sunday on the Long Island Expressway, near Manorville.
Scott Martella, 29, of Northport, a communications director for Suffolk County Executive Steve Bellone and a former aide to Mr Cuomo, was killed.
Police said the driver of an eastbound Subaru Outback, Carmelo Pinales, 26, of Hicksville, apparently lost control of his vehicle, crossed into the westbound lane, went airborne, and struck two vehicles, a BMW and a Honda.
Mr Pinales and his 27-year-old sister, Patricia Pinales, of Westbury, were killed. His 10-year-old son, Christopher Pinales, died of his injuries in hospital later.
Two others in the Subaru, including the three-year-old daughter of Ms Pinales, were treated for non-life threatening injuries.
A passenger in the BMW, Isidore Adelson, 81, of Westhampton, died of his injuries late Sunday at a hospital. Three others in the BMW, including Mr Adelson's wife, were also treated for non-life-threatening injuries.
Mr Martella, who was driving the Honda, was pronounced dead at the scene, police said. His 29-year-old fiance, Shelbi Thurau, of Northport, was taken to hospital with non-life threatening injuries.
Mr Cuomo said Mr Martella had served in his administration for more than four years. He called him a "dedicated, beloved public servant who worked day in and day out to improve the lives of his fellow New Yorkers".
Mr Bellone said: "Scott dedicated his all too brief life to public service and to helping others.
"My thoughts and prayers are with all those who lost their lives and suffered injuries in this horrible accident as well as their families."
Suffolk County police said detectives were investigating whether speed was a factor in the crash.