Answer
Axel von Fersen was accused in 1810 of involvement in the death of Charles August, Prince of Södermanland, the younger brother of King Gustav III of Sweden. The accusation stemmed from a misinterpreted comment made by Fersen during an opera performance, which, when repeated to Charles August's wife, was taken as a slight against her. This triggered a physical confrontation between Charles August and Fersen, resulting in the prince's death.