FARMINGTON — Police are still investigating a motor vehicle accident that left a 16-year-old boy in critical condition at Maine Medical Center.

The boy was a passenger in a 1998 Chevrolet Cavalier, which went off the road and struck a tree at the intersection of Chestnut Hill Road and Dodge Cross Road about 8:30 p.m. Sunday. There is no new information as to why the car went off the road, police said.

The driver was Shane Skibinsky, 24, of Calgary, Alberta, according to police. Skibinsky and another passenger, a 16-year-old girl, were treated and released from Frisbie Memorial Hospital, police said.

The girl was outside the car when rescue workers arrived. Skibinsky and the boy were extricated by the Farmington Fire Department.

The boy was taken to Frisbie Memorial Hospital, where the seriousness of his injuries prompted officials to have him transported to Portland, Maine. The boy was listed in critical condition Monday afternoon, police said.

Assisting the Farmington police and firefighters were Milton Police, Farmington Ambulance and the New Hampshire State Police Technical Accident Reconstruction Unit.