After some people hinted to me that Deej20 was a griefer, and we have been researching on his username, we found out that he poses on other servers as a blond, 17 year old canadian girl while he is clearly not a girl in teamspeak and has a different picture there, too.
So the picture here on teamspeak that he is using is this. Not sure which one of the two he is, though. Looks like two brothers to me. Same nose, same mouth.
He was was banned from several other servers already. Today he griefed some house in spawn right in front of my eyes (I was invisible). So he is banned from the server and team speak now.