How many reports for griefing does it take for action to be taken against someone?

Just had a terrible ranked game where our 4th pick called himself an ezreal one trick pony and was asking for the earlier picks to snag ezreal for him. They didn't and then the enemy team picked ezreal, so our adc decided he was going to troll by picking garen and going to the top lane to dance in place, soak up exp from our jax, and give kills or not assist in killing the enemy.

After we ff'd at 20, he responds in all chat "freelo" and then in the end game lobby talks about deranking and how he doesn't care about the game or the account.

I would hope that it only takes one instance of pulling shit like this for action to be taken against someone. But I'm curious is he going to punished for this anytime soon?