A few games ago I got into a game with someone that was on my last team and he was very tilted and toxic. Then the next game he was on my team yet again, in pre game lobby he was saying "I hope you end your life IRL" and some other toxic stuff.
We load into the game and he afked. There was a Rioter on the other team and I asked him if he could check out our Janna's chat logs, he told me to kms irl. The Rioter responded saying "Report him, send a screen shot to riot support, and that should take care of it". As im writing this now 12 hours later, the player is still playing League.