Player fed, abandoned killing himself to jungle creeps. After dying a few times he started to feed, drop items around the map, drop items in the allies inventory. He stole the Roshan, continued feeding, dropping items across the map, including the team's own neutral items. If that were just the case he wouldn't be making this post.
The same player after taking multiple reports probably got low priority. He logged into a secondary account and dropped into another game on my team. In this secondary account the player repeated the same thing, with the difference that he started to do it from the first minute. Following me on the map, dropping iron branches in my inventory, gave first blood to mid opponent and continued incessantly feeding, dropping items and destroying the game.