Suffolk County Police Sixth Squad detectives are investigating a motor vehicle crash that killed a teenager in Yaphank Monday afternoon.

A man was driving a 2004 Jeep eastbound on the Long Island Expressway, near exit 66, when he struck a 2018 Alfa Romeo  at approximately 2:20 p.m. The Jeep then hit the guardrail and flipped over the embankment, landing on the LIE Service Road.

Two passengers in the Jeep, a female, 18, who was sitting in the back seat, and her mother, 40, who was in the front passenger seat, were both ejected from the Jeep. The 18 year old female was transported to Long Island Community Hospital in East Patchogue where she was pronounced dead.

The driver, 22, his aunt and a third passenger, the 12-year-old daughter, all of Riverhead, were transported to Stony Brook University Hospital with non-life-threatening injuries.

The driver of the 2nd vehicle, 55, of Old Bethpage, was not injured.

Both vehicles were impounded for a safety check.