RedactedNarrative: On August 29, 2021 at 1043 hours, units were dispatched to Oakley Reservoir in Cassia County, Idaho for a report of boat that was sinking and the operator had not resurfaced. When I arrived I noticed a 20-30 mph wind with rolling waves in the water. I was advised by witnesses the operator had arrived at the reservoir around 0730 hours and had been trolling around the reservoir. Witnesses noticed the boat sinking on the northeast side of the reservoir with the bow pointing in the air. The operator had not resurfaced and was later located and pulled out of the water. Witness stated the male subject had a life jacket on his arm but was not able to get in on. The male was unresponsive and life saving measures were taken. CPR was performed for approximately 45 minutes but were not successful.