1) Dode had a valid reason to kill you. You killed an inno rdmer or not how is dode meant to know that for SURE. All he knows is that you killed an inno and that this is a valid reason to kill you.
2) Dode simply followed the rule of 2.5 Player Versus Player
If two individuals are fighting and you have no proof which could be the traitor, you must wait before joining in the fight until one player dies and they either; identify the body/the round ends/you question them.
He waited for you to fight. He questioned you and made up his mind that you killed an inno and acted on that.