You do not have the right to know who said these things about you. (You might eventually learn if your sued, but I wouldn't advise it.) Your employer will deny and deny again and again ever having told you that he would fire you if you talked to an attorney. Although my advice to you is to get out of that job quickly, attached are some files related to your request for help.
Here are some examples of what defamation is and is not
ATTACHMENT 1 - FILE COPY:
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Defamation is written or spoken injury to a person or organization's reputation. Libel is the written act of defamation, vs. slander, the oral act of defamation.
All wrong: "My neighbor John Smith is a stinking lush." This is wildly defamatory: an unproven, malicious ("stinking" and "lush" instead of "alcoholic") statement about a private individual.
Getting better: "Governor Smith consumed 14 glasses of whiskey last night at The Watering Hole Bar. In my opinion he's an alcoholic." The proof is a bit hazy -- getting drunk once does not prove alcoholism -- but a governor is a public figure with less protection than John Smith, you have clearly separated fact from opinion, and there is no particular evidence of malice.
Pretty safe: "Governor Smith consumed 14 glasses of whiskey last night at The Watering Hole Bar. I wouldn't be surprised to learn he's an alcoholic." This is entirely fact, with no clear evidence of malice, about a public figure.
What defamation is not.
Generally, a statement made about an undefinable group of people or organizations cannot be defamation. Take, "Real estate agents are crooks." It's defamatory enough, but there is no identifiable victim.
"Most of the agents at Smith Real Estate Company are crooks" is getting dicier, but it is still hard to define the victim.
"Smith Real Estate Company is a crooked company." Wham! You have a victim: Smith Real Estate Company.
For more information the place to start is Bruce Sanford's Synopsis of Libel and Privacy. It's an inexpensive, understandable little book, with checklists of words and people to be avoided. (This is actually written for journalists trying to avoid defamation. But it's also an excellent, readable book for deciding whether you've been defamed.)
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In attachement 2, note the heading "weighing the economics of a defamation case.
ATTACHMENT 2 -- FILE COPY
Defamation (formerly Libel and Slander)
A defamation is an untrue statement which tends to bring the subject into disrepute; the distinction between libel (written defamation) and slander (spoken defamation) has been abolished in Illinois. O'Donnell v. Field Enterprises, Inc., 145 Ill. App. 3d 1032, 491 N.E.2d 1212 (1986). An essential element of a defamation is damages in the form of injury to reputation in the eyes of others. Marczak v. Drexel National Bank, 186 Ill. App. 3d 640, 542 N.E.2d 787 (1989). A statement is "defamatory" if it impeaches a person's integrity, virtue, human decency or reputation and thereby lowers that person in the estimation of the community or deters a third party from dealing with that person. Muck v. Van Bibber , 223 Ill.App.3d 830, 834 (1992).
Need to prove damages. The person defamed must prove "special damages" (actual loss or injury) unless he or she can show that the defamation falls into one of four special categories that are per se defamatory: (1) crime; (2) accusation of carrying a loathsome disease; (3) imputing inability to perform or want of integrity in the discharge of duties of office or employment; and (4) prejudicing a person in his or her profession or trade.
Statement must be published. The statement must be published; that is, made to someone besides the subject. If someone calls you a name to your face, but does not repeat it to anyone else, that is typically not defamation.
Statements in lawsuits privileged. In Illinois, statements made in court, in a court pleading, in a complaint, or to a quasi-judicial agency (such as the EEOC) are generally held to be absolutely privileged from a suit for defamation. E.g., Medina v. Spotnail, Inc., 591 F. Supp. 190 (N.D. Ill. 1984). Persons defamed in such complaints are unfortunately left without legal remedy because public policy encourages people to make their accusations of wrongdoing without fear of reprisal. Thomas v. Petrulis, 125 Ill. App. 3d 415 (1984).
Innocent construction. Illinois has an "innocent construction" rule whereby a statement that is reasonably capable of a nondefamatory interpretation, given its verbal or literary context, should be so interpreted. Mittelman, 135 Ill.2d at 232. The rule is based upon context. Whether a statement is reasonably susceptible to an innocent construction is a question of law to be decided by the trial court. The trial court is required to focus on the "predictable effect" the statement had upon those who heard or read it. For example, the phrase "guilty of willful misconduct and malfeasance" in a corporate resolution firing an employee has been held to be a statement that clearly accuses the employee of a want of integrity in the discharge of the duties of employment. By comparison, the statement that an employee was terminated because of "lack of performance", without greater context, can be innocently constructed, since there may be explanations as to why the employee did not perform which do not reflect negatively on the employee.
Remarks relating to crime. While such allegations are per se defamatory, removing the need to prove special damages, a per se case may result in only nominal damages (say, $500) unless greater actual injury can be shown.
Weighing economics of a defamation case. Clients must take a realistic look at whether a defamation case would make economic sense. While defamation results in strong wounded feelings, often the passions which precipitate a lawsuit seldom persist to its conclusion, and diminish with each successive invoice from the lawyer.
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Good luck to you.
hmmbrdzz