At some point prior to 1899, Dutch killed the brother of his one-time associate Colm O'Driscoll, who in return took Annabelle's life. Her death would start a long-standing feud between the Van der Linde gang and the O'Driscoll Boys.
Events of Red Dead Redemption 2
Annabelle was mentioned several times by Dutch, Hosea Matthews and Arthur Morgan in conversations between the three. She is later mentioned during a confrontation between Dutch and Colm; whereas Colm claims he didn't particularly like his brother, Dutch firmly replies that he did like Annabelle.