A 5-year-old boy died Thursday after a single-vehicle crash in rural Hancock County.

A Maine State Police trooper came upon the crash at the intersection of Routes 9 and 193 near Beddington at about 11:25 p.m. on Thursday, Shannon Moss, spokesperson for the Maine Department of Public Safety, said in a news release Friday.

The trooper located the boy, “whose condition was rapidly deteriorating,” in the front passenger seat, Moss said. Despite lifesaving efforts, the 5-year-old was pronounced dead at the scene.

The boy’s father, Dion Campbell, 33, of Indiana, was the driver of the vehicle, Moss said. Campbell and his 10-month-old daughter, who was also in the vehicle, were transported to Northern Light Eastern Maine Medical Center with non-life-threatening injuries, Moss said.

A preliminary investigation indicates the vehicle failed to stop at a stop sign, Moss said, and then struck an embankment. It’s believed neither child was properly restrained at the time of the crash, Moss said.

Route 9 was closed for hours while the scene was investigated, Moss said.

The Aurora, Cherryfield and Osborn fire departments, as well as Bold Coast and Northern Light EMS, assisted in the response.