Reporting players other than just at the end of a game. (Champ Select)

TL;DR: Needs to be a report button in Champion Selection.

So this has been happening quite recently, where people will troll in champion select with abuse and such , but as soon as they get in game tone it down ALOT. I just played a game, where everyone didn't do so well, but the chat wasn't exactly aggressive or anything, just a small amount of anger from one particular player (who did just as bad as everyone else and was playing teemo jungle). I didn't report him as it wasn't particularly extreme, but I got him in the text queue and as soon as i joined champ select i was being spammed with abuse. The guy then proceeded to abuse everyone in the champ select, mainly me, but everyone else too. His reasoning was totally BS aswell saying that i was trolling in the game before (i did just as bad as everyone on my team) and he proceeded to pick an offmeta or "troll champ" in a lane that another player had already selected. There needs to be a way to report in champion select and see the writing within it. I hope the new tribunal puts this into play!