I'm sorry I didn't take a screenshot, but I hope the log from lagabuse (playdota) bot should be more then enough proof.

The game log is here: [url]http://lagabuse.com/stats/game/5048185[/url]
And here is the relevant quote:
37:36 HotDoggy [All] jebem vam po mater svima u usta (I dont think I should translate, but I can if needed)

Please note that I'm aware this should be posted in the lagabuse forum, but it's not a playstyle report but a family flame one, and as such concerns the server as a whole.