The cheater's Dotabuff is http://dotabuff.com/players/71401821. Currently top #1 on Europe Leaderboard.
7.8k SOLO MMR. He was 4.9k SOLO MMR after calibration..
He is currently changing his Steam name and Steam avatar every match.
http://steamcommunity.com/profiles/76561198031667549
STEAM_0:1:35700910

So he's been cheating since ranked matchmaking came out.
http://www.dotabuff.com/matches/542945640
http://www.dotabuff.com/matches/542921480
http://www.dotabuff.com/matches/542707941
http://www.dotabuff.com/matches/542904980

Same player feeding him and these 4 matches were done in 2 days. Coincidence?

Oh, you think that's just it?
http://www.dotabuff.com/matches/589835599
http://www.dotabuff.com/matches/589891573
http://www.dotabuff.com/matches/589955546

Yeah, you get my point, there are tons of matches like these. But now he doesn't do that anymore, instead he is using an armlet script which calculates incoming damage, stuns, damage over time and it works well with Huskar. It actually turns him into a God and he pretty much wins every single game because of this stupid cheat.

Please Valve, get rid of him, he ruined too many pubs and he obviously has no indention to stop.