Hacks are real?

So I was playing this game PvP Normal Mode. I played as Master Yi and I was well aware of the patches to him. Since I main Master Yi, I picked him and went into the game. 18 mins in......good game about to kill the Nexus. Out of nowhere an unskilled player comes into the crowd and kills everyone. Well I did know that he might have used all the special abilities. The thing is he was AFK the whole game, when he came to us he was only lvl 1 :/. People said he hacked, I said he didn't until that moment when he killed me (Had Bloodthirster, Ravenous Hydra, Nashors tooth, Berserker's Greaves, Infinity Edge, much health) I was killing everyone, lifestealed my health back to full when this guy comes and kills me in 2 hits. :3 .We all agreed that we would report him but instead I'm creating this discussion. He had killed me really fast and everyone else too. I hope this issue gets taken in and gets discussed as I faced 2 defeats in a row with this guy in the opponent team. When i asked him if he had been hacking he had told me "No... kid, I'm better than you is why. Lol kids." We had agreed to mute him but somehow he was able to talk. Please take this in and We ask you ,the people, to help us keep this League of Legends Community safer, better and more friendly. Somehow the match history does not show up and I did not get the stats page after we had faced the defeat. Thank you for reading this. <3

Your's Truly, Michael.

If any screenshots or the summoners name is needed please comment down.