It is not quite as simple as "there is either defamation or not." A lot needs to be considered before determining if a statement or statements are defamatory (context, exact words communicated and to whom and why, reactions to what is stated, etc.).Embellish? What are you talking about? There is either defamation or not. If there is, you, Proserpina and Zigner should shut up and stick to what you know!
While I agree that falsely claiming someone has created a hostile work environment or falsely claiming someone is a serial killer could be considered defamatory under some circumstances (and even defamatory per se), the fact that these statements were made is not enough to prove defamation.
In the described situation, Joeinca1130's reputation does not seem to have been injured by the statements alone but rather by Joe's acts and actions in the workplace which gave rise to the comments. His behavior could potentially support the statements as opinion based on personal experience. The statements may not have been related as, or understood to be, statements of fact (did anyone believe Joe was a serial killer?).
In other words, all facts matter. I don't disagree that Joe might want to contact an attorney in his area for a review of these facts.