Do you guys know how I/the site administrator could make a forum a little bit more secure? We are a sim league and 2 gm's that weren't active got fired, then they came back and hacked the site, which deleted every post.

Now someone is hacking users. The hacker posed as a gm and actually wrote up a press release(which is weird since it seems people are too lazy to do them in our league). Now the commish/administrator said he's going to be away for a couple of days and came back early. I tried to talk to him on YM before he left and he said some weird stuff and told me that he was drunk later. Now me and another guy are skeptical and wondering if he's being hacked.
Any ideas on how to secure forum.