BERLIN (AP) — German authorities have begun recovering the bodies of three people, believed to include one of Russia's richest women, who were killed in a small plane crash Sunday.

The dpa news agency reported Monday that authorities were unable to recover the bodies or examine the charred wreck earlier due to darkness.

Russian airline S7 Group said co-owner Natalia Fileva was aboard the single-engine, six-seat Epic LT aircraft that crashed and burned in a field as it approached the small airport at Egelsbach near Frankfurt. The business publication Forbes.ru has estimated Fileva's fortune at $600 million.

German police have said there were two Russian citizens on board but haven't provided any positive identification of the occupants yet.

The cause of the crash is still unclear.