You need their SteamID in order to report them, as we have to be sure.
If someone is currently connected to the servers
Go to:
http://stats.skial.com/
Select server type: tf (vanilla), tfcustom (vsh, dr, etc.), tftrade (trade eu, us, etc.), tfidle (idle)
Select server name: this is the name of the server you connected to, usually on the scoreboard in game
Select player name: this is usually their in-game name, if they have just changed their name - it could be their last one
Copy the "ID" that is displayed on this screen
If someone has just left one of the servers
If you know that they recently killed/were killed by someone
Follow the steps above, but instead - select the player they killed/were killed by
Select Events on the tabs ("Names", "Events", etc.)
Find the row that has their name on, click their name
Copy the "ID" that is displayed on this screen
If you don't know someone they recently killed/were killed by
Go to
http://stats.skial.com
Type their name into the "Search Name" box
Search through these until you find the right profile
If you have their Steam profile
Find the link to their Steam profile (ie.
http://steamcommunity.com/id/lsrwLuke)
Copy everything after /id/ or /profiles/ (ie. lsrwLuke)
Go to
http://steamrep.com/
Paste into the "SteamID32, SteamID64, or Custom URL" box
Click "Search", you will get something like
http://steamrep.com/search?q=lsrwLuke
Below the profile image, is a box with lots of information:
Copy the information after "steam3ID"