Frank Diskin, a longtime coach and athletic administrator in Kansas and the Kansas City area, was killed Thursday on a rafting trip just west of Fort Collins, Colo.
An autopsy conducted Friday ruled the cause of death as drowning with complications from heart disease, said Greg Fairman, investigator for the Larimer County Coroner's Office.
The raft flipped and dumped four people into the high-flowing Poudre River. One other person was injured.
Diskin, 69, most recently served as activities director at Parsons High School before retiring in 2010.
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He was the athletic director at Rockhurst University in Kansas City, Mo., from 1985-2007. A native of St. Paul in southeast Kansas, he also was an assistant athletic director at Washburn University and athletic director at St. Mary of the Plains College in Dodge City. He also coached basketball, baseball, football, softball, track and volleyball.
Diskin was sharing a raft with several family members when it flipped Thursday afternoon in the Mishawaka Falls area, according to the Larimer County Sheriff's Department.
The rafters were wearing wet suits and were part of a commercial rafting trip operated by Rocky Mountain Adventures. Two other people were rescued from an island on the river, and a fourth sustained an apparent broken leg, authorities said.
Diskin was swept about 1 1/2 miles downstream before he was pulled from the water. CPR was performed, but Diskin died at the scene, the sheriff's department said.
Recent rains and mountain snowmelt has caused the Poudre River to run high. The U.S. Geological Survey said the river was running "much above normal" Thursday afternoon and was flowing at 276 percent its normal mean for the date, the Denver Post reported.
Diskin was the third person to die this month in Colorado's recreational rivers, according to the Post. There were four rafting or tubing deaths in the state at this point last year.