Player behavior system and griefing, how does it work?

Hello,

I revently played an ARAM with an Ekko who kept taking up Zilean bombs and running into his teammates, on purpose (he followed us if we tried to get away from him, pretty obviously). After calling him out to stop it, he said "Allahu Akbar" (isn't this enough evidence?) and that he was trying to dodge. I told him that this isn't the case, because he even E'd into his teammates. After I told the rest of the players that i dont like this, and that they should consider reporting him, he said that we also should report syria.

After the game I reported him for griefing and hate speech (I think that his statements about syria were at least borderline hate speech and has no place in League of Legends, but feel free to educate me, if I am wrong). WhaT I want to know now is: how does the Player Behavior System determine if he was griefing? Not only in this case, but also things like getting open mid forced onto you. The open mid thing might be easier to detect, because it will be written somewhere in the chatlog, but how about thing like zilean bombs. There are no real indications in the chat, still it bothers me and ruins my experience and diminishes our chances to win, even if only for a little.

I'm really looking forward to getting some answers and want to thank everyone who wants to participate in this discussion. Have a nice day, Karboilt.

edit: cleared up some wordingstuff