The bodies of two friends who vanished after attending an Oklahoma music festival last month were discovered inside a van submerged in a lake and authorities said Tuesday that they do not believe there was any foul play.

Okmulgee County Sheriff Eddy Rice told the Tulsa World that the bodies of 20-year-olds Benjamin Baber and Cody Parrick were located Sunday in Baber’s minivan, which was submerged in the flood-swollen Lake Eufaula.

The men had been missing after the Rocklahoma festival for 16 days before receding water levels revealed the top of the van.

Mayes County law enforcement officials and volunteers conducted a search on more than 400 acres around where the festival took place. Family members say Baber and Parrick had three-day passes for the Rocklahoma performances and were planning to be there for the entire weekend.

Family members said the men had been best friends since they were in a pre-kindergarten class together. It’s unclear how the vehicle ended up in the lake but Rice said Baber was a very inexperienced driver.

The Associated Press contributed to this report