Feeder, intentionally griefing/feeding running down mid, how do I get a person like this punished?

So I'm just playing normally were vs plats and diamonds, you know whatever.

But this rengar literally from the start to the end just ran it down mid as much as he was alive. Afk'd in fountain and then continued feeding. ( I mean he was literally: Spawning, going to mid from fountain dying, respawning.)

Dunno if posting this is against the rules but running it down mid, and straight up afking are different. He was being malicious, not just upset.

(Replay)http://www.replay.gg/search/na/anivy

(Leagues match overview) http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2298937628/49011214/eog?tab=overview

I've intentionally not written his IGN as I don't want him harassed.