After the deposition of Gustav IV Adolf of Sweden in 1809, the Fersen siblings were known supporters of the Gustavian Party, who wished for the son of the deposed monarch to be acknowledged as heir to the throne. Instead, Carl August, prince of Augustenburg, was chosen. Like her brother Axel, Sophie fell under false and unfounded suspicion of involvement in crown prince Karl August's death in 1810. Both Sophie and Axel were rumored to have poisoned August. They were pointed out in a satire named "Räfvarne" ('Foxes') as the poisoners of the crown prince, and were punished in the satire with death.