Reporting toxic players

I think we really need a report button outside of the end game lobby.. one that we can access at any time. What gave me this thought? Well.. i just had a player in an ARAM game add me afterwards and started saying stuff like "die with ur mum in car accidents ,chinese noob" (that was copied and pasted from the chat.. it was also the very first thing he said to me). He also went on to saying things like he cursed me(LOL??) and that i was going to die in a car accident which would chop off my head (how?) very soon. I felt like i had to report this person but as i had already left the end game lobby, i couldnt do so anymore.. and this person would just go on to ruin other peoples games and 'cursing' them as well. This didnt seem right to me so here i am making this post

Honestly, i could tell he was a toxic player just from looking at his name which was - blameunoob

Besides that, the main point i wanted to make was that a new reporting tool would be very useful as this wasnt the first time i had experienced something similar (and im sure im not the only one) where i wanted to report someone but i couldnt. This one was just a lot more extreme which prompted me to take this to riot and make this post

If by any chance at all that curse is real.. ive already let my friend know and im sure he'll contact riot to hopefully get an ip address and im hoping you guys could help out there as well (LOL but im sure theres nothing to worry about)