A 4-year-old boy who was not strapped into a child-safety seat was killed in a Long Island car crash over the weekend, authorities said yesterday.

Finn Egan was riding in a sedan with his mother, Emily Snyder, 29, and aunt Jennifer Snyder, 41, when their car collided at 6:45 p.m. Saturday with two other vehicles on Pulaski Road in Fort Salonga.

The boy died about four hours later at Good Samaritan Hospital in West Islip.