How to report a player outside of game?

Hello,

I just had someone add me from a previous game that I did not do particularly well in. I shouldn't have accepted their friend request but I wanted to see what they had to say - im curious like that.

Anyway they proceeded to just say death threats against me and tell me I should go kill myself and things like that. I have pretty thick skin, it doesnt bother me, however I do think riot should be made aware of this offense because it can be very severe and damaging to others. If they did it once, (assuming this is their first time) they will probably do it again.

So if anyone can point me in the direction of where I can contact and report this person wit ha full chat log it would be greatly appreciated.

Thank you!