If you see a player on the server killing random people for no reason and there are no admins online to assist, here's a guide on how to report them.
You can press f8 to open up a damage log that will look like this
http://imgur.com/YoM8nIs
Regulars won't able to see logs of the current round. Logs will show up after the round ends.
You can click the current round button to switch back and forth between rounds for the logs. (only SO and Staff are