The 19-year-old driver of a pickup truck that struck a private ambulance Sunday night near the Arvenues mall died nearly 24 hours after the crash.

A 18-year-old woman passenger died immediately after the wreck, which also injured five other people.

The Florida Highway Patrol said a private ambulance turned left into the path of the northbound pickup truck at about 8:30 p.m. on Philips Highway just south of the intersection with Interstate 95. The driver of the ambulance told troopers he had a green arrow, but the cause of the crash remains under investigation.

Megan Bunn, of St. Augustine, a passenger in the Chevrolet Silverado and died at the scene. The driver of the pickup, Michael Linder -- Bunn's boyfriend -- was transported to Shands-Jacksonville Medical Center, where he died late Monday.

Three other people in the pickup were also injured: Shyenne Morgan, 17, is in serious condition at Shands; Cameron Waddington, 18, is in serious condition at Baptist; and Jonathan Rasnik, 28, was treated at St. Luke's Hospital.

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Troopers said no one in the pickup was wearing a seat belt. Beer was found in the vehicle, but it was unopened and the FHP did not know if alcohol played any part in the crash.

Brian Gray, 25, driver of the Liberty Ambulance, and passenger Julie Raymer, 44, were also hospitalized. On Monday, Gray was listed in serious condition and Raymer was in stable condition.

Bunn's family is in shock that her life suddenly ended just days after they were all together to celebrate Thanksgiving.

"She hugged everybody and kissed everybody goodbye, even our neighbors. That's something she hadn't done before," said Bunn's aunt, Ginny Carter. "I think everybody is in shock and saddened and her life ended when she was so young."

Troopers would like to talk with anyone who witnessed the crash as they continue the investigation. According to the FHP report, charges are pending.