this guy just troll pick and afk in the game, didn't attend any teamfight whole game.
Screenshot here

hate ******* trolls like that

Right start, wrong execution.

First, report after the game. That's what the button is for. If you have more evidence from a pre/post game chat, send these screenshots to Support. They can handle things like this. The forums aren't the place to actually report players. More specifically, name and shame on the forums is against the rules. I suggest you remove the names from your post, and take down the screenshot.