Authorities are investigating after a body was found at Walnut Creek State Park.
A lake-goer launching a boat -discovered the 49-year-old's body.
Oklahoma highway patrol says the man went missing Saturday night during a fishing trip.
After spending Sunday morning searching, his friends still couldn't find him.
Investigators believe he died by drowning but aren't yet certain. The Medical Examiner will determine the cause of death.
Walnut Creek State Park is west of Tulsa on Keystone Lake.