Delete someone else's post on my forum

[gracec]

Someone posted a bunch of spam posts on my forum using the username Khei:
http://www.icitouchtech.com/#!gechic-monitor-forum/c22ej

How do I delete another person's post? It is spam and it is not related to my website at all. I read somewhere that it cannot be deleted and I cannot find anywhere on the forum that allows me to delete it. I am the administrator of my site and it seems very silly I can't delete a post on my website.

[GregChapman]

Click on their username/avatar.

That takes you to their profile page where there is an link "Ban this user".

That takes you to a confirmation screen where you can also delete all the user's posts.