If by background, do you mean an official record, or activity only?
I know of several transgressions against the law by staff, but I can only think of one who I know, without a doubt, has a criminal record, and that is Richard Armstrong. He drugged and raped Twila Stephenson (Quest family head) while they were both working as escorts. (post-CEDU)
However, I could be wrong, since there was no criminal trial. Only a civil one. Richard was ordered to pay Twila around $150,000.