To clarify the character profile I suggested:

The suspect is obsessed with respect. If he feels he has been slighted he will go after you. He will *act* to obtain respect. This would likely include engaging in a friendly chat (not really friendly though). He might follow it up with a little sabotage, or backstabbing, rumor, or inuendo. This person is not a loner. He does not have trouble socializing. He will act in a critical manner to expose your mistakes publicly in order to regain the respect that he feels he has lost. It will be obvious to the victim, but not necessarily to anyone else. His actions might in fact be championed by others.

I would be looking very hard for people like this.