A telephone notified rescuers when a vehicle struck a tree early Sunday in Nebraska, killing all six teenage passengers.
Five males in a Honda Accord died in a 2:15 a.m. collision in Lincoln, 3 miles east of the state Capitol, police said. A 24-year-old lady in serious condition died at the hospital.
The 22-year-old driver was among those killed. 21-, 23-, and 22-year-olds were the other casualties.
Police are investigating the cause of the collision, which was automatically reported by an iPhone when its owner didn't react.
Lincoln Police Assistant Chief Michon Morrow called it "the deadliest accident in recent memory." We can't recall a similar accident.
Sunday afternoon, investigators hadn't found any witnesses to the incident, making it tougher to assess what occurred.