The Iowa Department of Natural Resources is investigating a Waukee man’s death after he suffered a possible medical emergency on Clear Lake.

The DNR said 28-year-old Daniel Linderman was tubing behind a boat when he fell into the water Saturday around 2:30 p.m. Officials said he was swimming back to the boat when he stopped and went face down into the water. A DNR water patrol officer was nearby and provided CPR.

Linderman was taken to the hospital where he was pronounced dead. Officials are now waiting on an autopsy to determine what happened.

The DNR said Linderman was wearing a life jacket.