Berlin resident Heather LaFlamme, 21, was identified Thursday as the New Hampshire resident most seriously injured in an accident on Martha's Vineyard Wednesday.

LaFlamme, the backseat passenger is a Jeep Wrangler, was in critical condition Thursday afternoon at Brigham and Women's Hospital in Boston. A helicopter flew her off the island shortly after the accident, which took place about 2 p.m. Wednesday on Barnes Road Extension in Edgartown.

Three other people were hurt in the accident and are listed in serious condition at Bay State hospitals. They are:

The driver of the Jeep, Thomas C. Jones, 51, of Dummer, who was admitted to Martha's Vineyard Hospital.

Rear seat passenger Seth Jones, 26, of Dummer, who was flown to Beth Israel Hospital in Boston.

Front-seat passenger, Margaret Jones, 51, of Dummer, who was also flown to Beth Israel Hospital.

State police said they continue to investigate the accident, which took place when the Jones' Jeep was broadsided by a 2009 Volkswagen SUV, driven by Benjamin T. Johnson, 19, of Cambridge, Mass.

He was evaluated for possible injuries at Martha's Vineyard Hospital and released.

Police said it appears the southbound Jeep, which had the steering wheel on the right-hand side, pulled off to the right shoulder of the road and entered into an apparent U-turn.

The Volkswagen Tiguan was also southbound. The accident caused the Jeep to roll over and the Volkswagen Tiguan to veer off the road.

State police accident reconstruction specialists and criminal investigators are taking part in the investigation. Police said they are looking into the speed of the SUV and whether the odd placement of the steering wheel affected the Jones' vision.