Two friends who were found in a submerged vehicle in Lake Eufaula in June died of accidental drowning, according to the state medical examiner's office.
The bodies of Ben Baber and Cody Parrick, both 20, were discovered June 7, more than two weeks after they were last seen at Rocklahoma in Pryor.
The longtime friends failed to return home after the festival's first night, eventually prompting a missing persons investigation in Okmulgee County where both men lived and a multi-county search that included various law enforcement agencies and a number of volunteers.
Around the time of the festival, much of Oklahoma saw torrential rain that flooded roads across the state. After waters began to recede, Baber's van in which the boys traveled to and from Rocklahoma was discovered by a McIntosh County man in the lake at the Onapa Boat Ramp.
According to the autopsy reports, Parrick was at the wheel and Baber was a passenger. Both men were wearing their Rocklahoma wristbands when they were found.
Okmulgee County Sheriff Eddy Rice said there were no signs of foul play.
The autopsy, which was released Friday, reports neither man had any injuries and the official cause of death is accident by drowning.