It happened on Sunrise Highway at 35th Street in Copiague around 7 p.m.
Amir Porterfield was walking at the crosswalk when he was struck by a woman driving a 1999 Subaru. Suffolk County police say Anne Williams remained at the scene.
But that's when another driver hit Porterfield while he was laying in the roadway. That vehicle fled the scene.
Porterfield and Williams were transported to Good Samaritan University Hospital in West Islip.
Porterfield died from his injuries.
Williams, 65, of Lindenhurst, was treated for non-life-threatening injuries.
The Subaru was impounded for a safety check.
Detectives are asking anyone with information on the crash to call the Major Case Unit at 631-852- 6553 or call anonymously to Crime Stoppers at 1-800-220-TIPS.
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