A missing Alzheimer's patient found Friday morning along the Chattahoochee River died in a hospital, Channel 2 Action News reported.

Richard Chang Lee, 72, went missing Thursday afternoon from his Duluth home.

A Georgia State Patrol helicopter spotted Lee lying face down, partly in the water, early Friday morning, and National Parks Service rescuers, aided by Gwinnett County police and fire departments, were able to rescue him.

"He was lying flat, but basically in the water about two to three inches," said Shawn Perchalski, supervising park ranger with the National Parks Service. "There’s no telling how long he’d been lying in the water."

Lee was responsive when rescuers reached him in a boat, authorities said. But he may have suffered from hypothermia because the water temperature was around 55 degrees.

The man reportedly died Friday morning from complications related to his age and conditions. His body was cold to the touch when he was found on the riverbank, authorities said.