Michael: We did a deal, a long time ago. Didn't go quite the way it was supposed to go. Wrong guy got killed.
So it is certain that Dave and Michael planned to kill Trevor in Ludendorff but instead Brad got shot and died.
Woah there. T doesn't know about the whole truth, does he? Is there any context Michael told Trevor in the game, or is M going to keep this unnerving secret for the rest of his life?
See also: Franklin saying he will still be with him despite M's history of betrayal