MADISON HEIGHTS, Va. -

Investigators are still looking at what caused a woman to die Monday afternoon in the James River.

Hope Stoeckel, a 69-year-old from Delaware, was riding in an innertube when she slipped out and went under water near Percival's Island.

She was pulled out and given CPR, but died before she could make it to a hospital.

Stoeckel was doing an excursion with the James River Float Company. The business is voluntarily suspending trips on the river in what it calls a "safety stand down," until the results of Stoeckel's autopsy come back.

A medical examiner in Roanoke is conducting the investigation.  The results may prompt a change in business and safety procedures, according to float company owner Mason Basten.

Witnesses say Stoeckel may have suffered a medical condition that caused her to fall out of her tube.