CLARK FORK - An older man drowned while fishing the Clark Fork River Saturday after an unknown malady caused him to collapse.

The 62-year-old Bonner County resident, whose name has not been released pending notification of family, set out during the morning to fish Twin Creek with a male and female friend. Spending their time around a nearby sandbar and standing in the water using waders, the party fished several hours without incident until the victim suddenly collapsed into the water.

It took the two friends 15 minutes before they were able to locate the victim. By this time, he was unresponsive. After notifying the authorities, they spent an hour-and-a-half using CPR in an attempt to revive the man.

Life Flight and EMS teams responded to the scene of the accident, but despite the best efforts of personnel, they were unable to resuscitate him, Bonner County Sheriff Daryl Wheeler said.

"There were a lot of folks working very hard to bring this man back," Wheeler said.

At this point, the exact cause of the collapse remains a mystery until a coroner's examination is conducted.

"I would keep away from trying to make any guesses," Wheeler said.