Chinese billionaire Lam Kok, his 12- year-old son and two other people are presumed to have died when the helicopter they were traveling in plunged into a river in France’s southwestern Bordeaux region Friday.

Police were searching the Dordogne River for the bodies, Anne-Cecile Dumonteil, deputy prosecutor at Libourne court, said by phone. Lam Kok, head of tea and real-estate company Brilliant Group, had just bought the Chateau de la Riviere vineyard for $41 million from James Gregoire, who was giving him an aerial view of the property from the helicopter.

The body of Lam’s 12-year-old son was retrieved from the river Friday, the South China Morning Post reported on its website Saturday. The fourth person in the helicopter was an interpreter, Dumonteil said.

Lam is a member of the Yunnan Provincial Committee of the Chinese People’s Political Consultative Conference, the report said. Brilliant Group, based in the province, also operates tourism, department-store and hotel businesses.