well in all technicality, yes. Gavrilo Princip killed the Archduke and his wife, but the meaning of the killing goes much further. In a drastic oversimplification Serbia was being abused by Austria-Hungary so he was angry and killed the archduke.

i know that i research the hell out of both world wars and their true causes

*Austria-hungry

well yea both of them

but Serbia commited the act that caused A-H to go to Germany and get issued the "blank check" that gave A-H freedom of action which would end up in A-H declaring war on the Serbians