TAHLEQUAH, Okla. — The Oklahoma Highway Patrol has released the cause of a crash that killed five students from Northeastern State University earlier this year.

In a report issued Wednesday, investigators say the Sept. 17 wreck near Tahlequah was caused by unsafe speed on a curve and a wet roadway. The investigators’ report says that the driver, 18-year-old Donovan Caldwell of Muskogee, was not impaired at the time of the crash.

The truck went off the road, slammed through a guardrail and plummeted about 35 feet (11 meters) into a creek, landing on its top.

Caldwell was killed in the wreck along with 18-year-old Jessica Swartwout of McAlester; 19-year-old Drake Wells of Thackerville; 18-year-old Rhianna Seely of Salina; and 18-year-old Lily Murphy of Gentry, Arkansas.