A teenager, her father and two younger siblings are dead after the 17-year-old drove off a cliff and into a river when she fell asleep while driving from Washington to Idaho on a family vacation, authorities said.

The family was reported missing Saturday morning after they were overdue for their arrival. A few hours later, a fisherman found their car overturned in the Salmon River north of Riggins, Idaho, the Idaho County Coroner said in a statement on Facebook.

The Spokane family was identified as 36-year-old Calvin “CJ” Miller and his three children: 17-year-old Dakota, 10-year-old Jack and 8-year-old Delihia. “All occupants succumbed to their injuries,” the coroner’s office said. 

“Our hearts are broken for this family and our thoughts and prayers are with them at this time,” the coroner’s office said in the statement. 

Deputies believe Dakota ‘fell asleep’ behind the wheel

Idaho County Sheriff’s Office deputies believe Dakota was fatigued and “fell asleep while driving,” according to an accident report obtained by USA TODAY. 

“Due to this, Dakota, drove off the highway, striking a large pile of rocks sending the vehicle airborne,” the report said. “The vehicle struck another large pile of rocks, flipping the vehicle over end and landing upside down in the Salmon River.”

Deputies believe the car fell 30 feet from the cliff and into the river where cold water filled the vehicle through the driver’s broken window, which caused the family to drown, the report said.