“Kill me, then. Voldemort, I welcome death! But my death will not bring you what you seek . . . There is so much you do not understand . . . Kill me, then! You will not win, you cannot win! That wand will never, ever be yours—"
-- Gellert Grindelwald's last words (DH23)
Voldemort had traced the Elder wand to Grindelwald, who he then visited in a lonely cell atop the tallest tower of Nurmengard. When Grindelwald defied Voldemort, the Dark Lord murdered him with a Killing Curse (DH23).