Rainer Schaller -- who owns Gold's Gym, among other brands -- is still missing after his plane disappeared off the coast of Costa Rica, and his gym's parent company says the plane crashed.
The RSG Group issued a statement Monday confirming Rainer, his family and two others were on board the plane when it crashed.
There is still no official word if Rainer died ... though there are reports two bodies were found, plus luggage and pieces of the twin-engine plane.