Skip to content Skip to footer

Table of contents

This Illinois Human Resources Manual is offered to you for free. Find state specific laws and regulations below.

Workplace investigations — Illinois

Under various civil rights, whistleblower and health and safety laws, it is either required or good practice for employers to investigate complaints or accidents and promptly take action. After a written or oral complaint is made regarding improper conduct, an affirmative duty may arise requiring the employer to investigate the allegations immediately. Investigation of complaints yields a number of additional, practical benefits for employers as well. Even when no complaint is made concerning improper conduct, an employer may be under a duty to investigate if the employer has constructive knowledge (reasonably should have known) of the conduct.

Practical benefits of conducting investigations

Defense to charge of harassment/hostile environment

It is critical for an employer to investigate claims of harassment or discrimination, as an investigation can be used as an affirmative defense to a hostile environment harassment charge under federal law. In other words, even if harassment or discrimination may have occurred, a strong anti-harassment and anti-discrimination policy, a thorough investigation and prompt remedial efforts might prevent the employer from being liable. In many instances, the plaintiff in a potential lawsuit against the employer must show that the employer knew or should have known about any harassment or discrimination that is the basis for the lawsuit. If the employer had a policy to redress complaints internally and the employee did not complain to management, he or she may not be entitled to pursue a claim. Likewise, if the employee complained and the employer took prompt action, then the employer might also have a defense to the harassment or discrimination complaint.

Limit liability for discrimination or quid pro quo sexual harassment

An investigation may also limit the employer’s liability. Although a lack of employer knowledge and prompt action are not defenses to disparate treatment discrimination claims or quid pro quo (this for that) sexual harassment claims, a proper investigation can still limit employer liability. If the employer immediately investigates any claims of discrimination, it may stop the discrimination or harassment, and thus limit the amount of the plaintiff’s damages or reduce the chance of a broader class-based claim involving other affected employees. Taking prompt action may be especially persuasive to a jury as a reason not to award significant punitive damages. Also, the employer may be able to limit the scope of the lawsuit to only those issues which the plaintiff/employee raised during the internal investigation.

Identify problem employees

As a rule, an employer’s investigation in response to an employee’s complaint should be directed at confirming the accuracy of the allegations and resolving possible issues, if any exist. Nevertheless, in the course of conducting an investigation, the employer may well uncover evidence of wrongdoing by the person making the complaint. Although it is unlawful for an employer to retaliate against a whistleblower in most circumstances, it is not technically unlawful for the employer to act on the information it uncovers. Assume that a company has a uniformly applied policy of terminating employees who make material falsifications on their applications and, in the course of investigating a failure-to-promote claim, it finds out that the complaining person made such a falsification. It generally will not be unlawful retaliation to terminate the person under these circumstances because the employer would be merely applying its policy uniformly. Such information could provide a basis to question an employee’s credibility, as well. Care must be taken, however, to avoid a claim that the company went out of its way to investigate the person making the complaint in reprisal for making the complaint, as the timing of any decision to discipline an employee who raised a complaint of harassment or discrimination may suggest a retaliatory motive to an objective fact-finder.

Defend claims relating to negligent retention

An employee who is harassed or discriminated against may bring claims alleging that the employer negligently retained someone it knew or should have known had a history of engaging in harassing or discriminatory misconduct. Such a claim would be strengthened if the plaintiff could show that the employer had received several prior complaints about the offender that had been ignored. Therefore, an employer that has a policy and a practice of investigating every claim of harassment or discrimination is in the a better position to defend a subsequent lawsuit for negligent retention claims. Alternatively, a strong practice of investigating claims coupled with an absence of investigations of a person could reinforce the argument of an employer that it had no previous knowledge that a particular employee allegedly tended to harass or discriminate.

Create a more agreeable workforce

Generally, a proper investigation policy creates a less litigious workforce. Employees who feel their complaints are taken seriously will be less likely to sue later. Many times, plaintiffs will say that if the employer had just treated them fairly after they raised their complaints, they would not be in court later. Investigations are beneficial for the employer generally because when a complaint is filed, the employer knows to keep an eye on the accused individual for possible future transgressions.

Gather information

Finally, an investigation is the employer’s first and most reliable source of information about the complainant’s allegations. Based on the investigation, the employer will be better able to make decisions about what disciplinary action should take place. Also, if a lawsuit ever arises out of the complaint, the investigation offers the employer some protection. The employer will also be in a better position to determine whether to offer to settle the case, and whether to indemnify or offer legal representation to an individual manager or employee accused of harassment or discrimination.

Procedures for conducting internal investigations

Determining if a complaint has been made

An employee has raised a complaint of harassment or discrimination any time he or she makes such an allegation to the specified person in the employer’s harassment policy (usually the human resources manager or other senior management) or reports the harassment or discrimination to management. But what about when an employee reports a complaint to a supervisor and asks the supervisor not to take any action? Has a complaint been made? Can the employer afford not to act on the information even though the reporting employee asks the employer to refrain from doing so?

These are not easy questions. Their answer in a legal sense may depend on the nature of the information reported and the identity of the person receiving the information. However, from a human resources perspective, it is never safe for any employee with supervisory authority or a management title to ignore any report of harassment, discrimination, or suspected retaliation, even if the complainant requests that no investigation be conducted.

In particular, all supervisors and managers must be reminded to report any complaint of harassment, discrimination, or retaliation for a prior complaint to the correct person, no matter how minor it seems or how informally it was raised. Managers or supervisors should not investigate complaints on their own unless they have been designated and properly trained to do so. Nor should they suppress information because they themselves doubt the legitimacy of the allegations or for fear that it will result in the termination of a valuable employee such as a star sales representative. It is important for managers and supervisors (and everyone in the employer organization) to remember that in the long run, it will be better for the employer to find out the truth regarding such allegations, even if it is uncomfortable in the short run. Managers and supervisors should also report any harassment or discrimination that they observe, even if there is no complaint.

There is no one right way to conduct an investigation, although there are lots of ways to make mistakes. The following summary illustrates common practices, but the key issue is to tailor the investigation to the needs of the situation, which can also involve considerations of privacy and cost effectiveness.

Next steps after determining a complaint has been made

When a complaint is made, a productive initial conversation with the complainant is often a critical first step in determining whether an official investigation may be necessary. Likewise, obtaining a complete and accurate statement regarding the complaint is essential to determine the extent of the investigation required. The following steps should be taken promptly in order to ensure that an investigation is effective.

Instruct the complainant regarding the investigation

The complainant should be told that his or her complaint will be treated very seriously by the employer, and that it will be investigated. The complainant should be reminded that the company’s policy prohibits any retaliation against an employee who makes a good faith complaint. Often, it is good to put this reminder in writing. The complainant should be advised to contact the investigator immediately if he or she feels that any retaliation is occurring. Under some circumstances the employee delivering the complaint should be told not to discuss the matter with others so that such conversations do not impede the effectiveness of the investigation. Finally, the complainant should be told that the investigation will be treated confidentially to the extent possible, but the investigator might need to discuss the matter with those necessary to the investigation or affected as a result of the investigation.

Careful consideration should be given before instructing a complainant, a witness, or even the accused to keep confidential the subject of the matter under investigation. Employees have the right to engage in concerted activity for mutual aid and protection under the National Labor Relations Act (NLRA), whether they belong to a union or not. Strict rules imposing confidentiality may coerce employees in the exercise of these rights by dissuading them from reporting offensive conduct to their union representative or banding together with other employees to oppose a practice that is arguably unlawful.

On the other hand, maintaining confidentiality during the course of an investigation may be important in getting at the truth. In addition, reports by some employees could be legally privileged by the attorney client privilege or the attorney work product doctrine. Because this privilege belongs to the company and not the employee, the employee is not free to waive the privilege by disclosing what was discussed with a company investigator, provided that investigator is an attorney or operating under the directions of an attorney.

Have the complaint reduced to writing either by having the complainant write out a signed, and dated complaint or by providing a written summary for the complainant to review. But even if the complainant fails to put the complaint in writing, it should still be investigated. It is best if the written complaint indicates:

  • Who harassed/discriminated against the complainant? (Include the name and work relationship to complainant.)
  • What did that person do? (Include specific statements, improper conduct which is the subject of the complaint, and any reasons that the complainant may believe initiated the conduct.)
  • Where and when did the conduct take place? (Include the first time, each subsequent time, and the last time the conduct took place.)
  • How did the complainant respond? (Did the complainant indicate the conduct was objectionable? Did anyone else? How did the offending party react?)
  • Were there any witnesses to the harassment/discrimination? (Have the complainant identify the witnesses’ names and what the witnesses may have seen or heard, and ask the complainant whether he or she told anyone about the improper conduct.)
  • Are there any documents concerning the harassment/discrimination? Did the complainant keep a diary or notes? Was there any email exchanged with anyone relating to the events which make up the basis of the complaint? (Have the complainant identify the documents and the witnesses’ names and what the witnesses may have seen or heard – and ask the complainant whether he or she told anyone about the improper conduct.)

Take detailed notes of the conversation with the complainant

Include the name of the interviewer, date, time and location of the interview, who was present, and length of the interview. This document may become an important piece of evidence in the event that the complainant or the alleged wrongdoer sues the employer. It is important that the interviewer document only the facts as stated by the complainant and not his or her opinions or conclusions about the interview.

Consider whether to ask the complainant what he or she wants

Asking the complainant about the outcome he or she hopes to achieve as a result of the complaint may set him or her up for disappointment. At this stage, there is no need to set his or her expectations. On the other hand, the requested relief may be very minor such as an apology or a minor form of accommodation. Knowing what is at stake from the complainant’s viewpoint may help the investigator assess credibility or allocate appropriate resources to the investigation. Eventually, the company will want to get an idea of what the complainant wants, and the investigator must decide when is the best time to ask that question.

Do not make promises or offer opinions

  • Do not promise complete confidentiality.
  • Do not promise that the alleged wrongdoer will not come to know of the complaint.
  • Do not promise to keep the complainant’s identity from the alleged wrongdoer.
  • Do not tell the complainant whether you believe him or her.
  • Do not promise that the alleged wrongdoer will be disciplined.

Do not discipline the complainant for reporting the complaint

Even if the complainant has complained to the wrong person or gone “outside the chain of command,” do not indicate that making the complaint could result in any sort of discipline for the complainant. This may be considered retaliation. If the complaint was made in bad faith without any reasonable basis, the law might permit the complaining employee to be disciplined, but such cases are exceedingly rare.

Consider allowing the complainant to have a witness present for the interview if this is requested

If an employee is represented by a union and requests union representation, the employer must permit the employee to be accompanied by a union representative before the employer conducts an investigatory interview of the employee if the interview could lead to disciplinary action for the person being interviewed. This does not give the employee the right to choose a particular union representative and does not authorize the employee to substantially delay the interview.

Identifying an investigator

Determining whether to engage an internal or external investigator is a very important decision with many potential legal ramifications. The chosen investigator must be well-trained and impartial. A wrongly chosen or biased investigator may discourage candid interviews or even the reporting of illegal conduct. An employer should choose an investigator who is experienced, properly trained and objective. Generally, an employer should have several qualified and trained investigators within the company, and may engage more than one investigator in any one investigation.

Many courts have held that whatever the employer does to investigate a claim of discrimination or harassment may be admissible in a lawsuit. Therefore, written materials may be obtained by the plaintiff, and the person who conducted the investigation may be called upon to testify. If the investigation is conducted at the request or recommendation of an attorney, the employer may be able to make an initial argument that the investigation is protected by the work product doctrine or the attorney-client privilege.

However, courts sometimes will not give this argument much merit. If the company reaches out to its regular outside attorney to conduct the investigation, it must consider that the attorney could be called to testify and may therefore not be available to represent the company in any subsequent lawsuit. There are several potential investigators available to the employer, including:

  • Human resources representative - One choice is the employer’s human resources representative. The HR representative should be trained regarding proper procedure, and should be impartial, thereby obtaining more accurate testimony from witnesses. The HR representative will normally bring a detailed knowledge of the company’s policies and procedures, thus shortening the time and reducing the cost of an investigation. However, if the employer uses an HR representative, the work will be discoverable.
  • In-house or outside attorney - Another choice is an in-house attorney or outside attorney. Either one can be properly trained regarding procedure, impartial, more familiar with legal ramifications, and can better handle accusations against high-level managers. However, even if the investigation is conducted by an attorney, the investigative notes may not be protected by the work product doctrine or the attorney-client privilege if the employer attempts to use the investigation as a defense such as commonly occurs in a hostile environment claim.

Initial discussion with the alleged wrongdoer

It is advisable to have two people interview the alleged wrongdoer in order to ensure that there is a witness to the discussion and, specifically, to any remarks which the alleged wrongdoer may make. If the alleged wrongdoer is a member of a collective bargaining unit, then he or she is entitled to have a union representative present during any interviews or investigations. However, the employer does not have to offer the alleged wrongdoer such representation unless he or she requests it.

The initial interview of an alleged wrongdoer is a critical part of the investigation. The investigator should reiterate that the employer takes the allegations of every complaint seriously by fully investigating them consistently with its policy. The interviewer should inform the alleged wrongdoer of the allegations made and review relevant employer policies with him or her. In addition, the alleged wrongdoer may be told that there is a possibility of disciplinary action if the complaint is found to be true, but that the company will provide an opportunity to respond to all allegations and that the employer has not yet determined whether any violation of company policy has occurred.

It is usually best to instruct the alleged wrongdoer to minimize contact with the complainant immediately, and to inform the alleged wrongdoer that they may be separated during the investigation. The alleged wrongdoer should be given a strict warning not to retaliate against the complainant, and, when appropriate, instructed to keep the matter confidential in order to respect privacy concerns, prevent rumors and protect the integrity of the interview process. Finally, the alleged wrongdoer should be advised that any violation of these instructions will be considered as possible grounds for disciplinary action up to termination. It is usually best to incorporate all of these instructions and warnings in a confidential letter or memo to the accused.

Identifying witness and relevant documents

It is normally important to interview all individuals involved with the complaint, including all witnesses identified by the complaining employee and the accused. Companies should also consider interviewing all employees who work closely with the accused. However, be careful when interviewing non-employee witnesses, as they are less likely to keep the matter private and may be less reliable.

Schedule meetings at a time and place so that they will not attract attention. Explain the need for confidentiality to the witnesses, and ask questions designed to discover the who, what, when, where, and how of the situation. The investigator should document all interviews, keeping in mind that all notes or other documents may become evidence in a future lawsuit, and be careful not to make unsubstantiated allegations or assessments. Be sure to talk to both the accused and the complainant. If the investigation lasts more than two to three days, follow up with the complainant and keep him or her informed of all progress – reassure him or her that the matter is being looked into very seriously.

Next, collect any relevant files, documents or statistics that may help verify or disprove the allegations. In a sexual harassment case, for instance, review any notes, calendars, and diary entries maintained by the complainant, including correspondence and emails between the complainant and the accused, or the complainant’s friends or supervisors. The personnel file of the complainant and the accused, desk files maintained by the supervisor of the accused, and investigation or discipline files for other individuals accused of similar conduct, should also be acquired.

In a disparate treatment case, identify employees who are similarly situated with respect to the complainant. Obtain and review relevant files or records regarding them. Generally, the complainant will identify several individuals outside of the protected classification who are believed to have been treated better. The employer should pull the files of those individuals, as well as employees whom the complainant’s supervisors feel are similarly situated with respect to the complainant. Files that may need to be reviewed include:

  • personnel files
  • payroll or compensation files or records
  • hiring, promotion or transfer records
  • evaluation forms
  • reduction in force plans or termination statistics.

Employer rules, policies, procedures and instructions should also be reviewed in most investigations. Electronic files which are relevant should be reviewed and saved. IT personnel should be alerted to save relevant documents and to ensure that relevant documents are not destroyed either intentionally or inadvertently in accordance with a routine record retention policy.

One issue which has arisen is whether the employer is entitled to review emails an employee may have sent from a web-based password-protected email account (such as a Gmail or Yahoo account, not the employer’s email), but using the employer’s computer systems.   Due to federal privacy laws governing electronic communications, employers should not attempt to access an employee’s personal email or social media accounts hosted by third parties without authorization, even if the employer is able to do so based on information readily available to the employer.

Take immediate steps to stop any wrongdoing

If the investigation will take more than one day, an employer should consider taking immediate steps to deal with the alleged wrongdoing – particularly any harassment. Consider:

  • giving the complainant the option of taking paid leave from work
  • giving the complainant the option of moving to a different work location on a temporary basis
  • instructing the alleged wrongdoer not to talk to the complainant
  • changing the supervisory reporting structure
  • giving the accused paid leave from work.

Be careful to avoid the appearance that the alleged wrongdoer has already been deemed guilty of the offense or that the employer has retaliated against the employee.

Preparing the investigation file and log

The investigation file should be complete, accurate and thorough. It is important to include:

  • a chronology of events
  • a chronology of the investigation
  • a list of all people involved or contacted
  • a list of all documents reviewed
  • all communications with those involved
  • witness statements
  • documents that establish or refute the issues investigated
  • physical evidence
  • investigator's reports
  • documentation of results or remedial actions
  • a summary of the allegations and responses
  • a complete record showing teh employer's prompt and appropriate action.

Employers should not include editorial comments or conclusions about credibility or the merits of the complaint, as the file may be admissible in a later lawsuit. Instead, the file should only contain objective, factual information. The file should not contain opinions, advice or letters from the employer’s attorney. Investigation files may include a log of all complaints and actions. Keeping the complaint logged is a good way to keep track of complaints within a changing workplace. The log also makes the employer aware of multiple claims against the same person or within the same group. The log should include:

  • date of the initial complaint
  • name of the alleged victim
  • type of claim
  • name of alleged accused
  • department/division involved
  • level of complaint (internal-informal, informal-formal grievance, lawsuit, etc.)
  • resolution and date
  • person assigned to investigate.

It is crucial to always keep the log confidential.

Reaching a conclusion

As a consequence of the investigation, the investigator should reach one of three conclusions concerning a complaint of wrongdoing:

  1. that the wrongdoing actually occurred
  2. that the wrongdoing complained of did not occur
  3. that the evidence was inconclusive, if the investigator is truly unable to determine whether the wrongdoing occurred.

However, a determination that evidence is inconclusive should not be used as a means of avoiding a difficult decision.

Validity of the claim

In determining whether the complained-of conduct occurred, the investigator should evaluate the credibility of all witnesses, considering whether the complainant’s story or the alleged wrongdoer’s story is consistent with the stories provided by other witnesses. The investigator should determine whether the complainant and the alleged wrongdoer were cooperative or appeared to be withholding information, and consider whether the complainant or alleged wrongdoer exhibited characteristics of lying (failure to make eye contact, squirming, internally inconsistent story, lack of details).

In addition, an investigator might consider the past history of the complainant and the alleged wrongdoer. Even if past complaints against the alleged wrongdoer were investigated and found to be inconclusive, multiple complaints may indicate that the current complaint is true. Alternatively, a history of baseless complaints by the same complainant or against the same supervisor may indicate that the current complaint is not valid or that it may have been made for ulterior purposes.


Finally, the employer must document any decision reached. Documentation should include a review of the complaint, a summary of each witness’s version of the relevant facts, and the investigator’s conclusion with an explanation of reasons. It is usually important that the investigator not make any pronouncements about whether particular conduct violated the law, because such a conclusion could be very damaging to the company in a future lawsuit. A lot of objectionable conduct may be inappropriate or in violation of accepted company norms, but not so severe or pervasive as to be a violation of law. Thus, it is not uncommon to find that the conduct violated the standard of behavior expected of employees, but that it did not constitute a violation of the employer’s harassment policy. For these reasons, it is important that investigation notes and recommendations steer clear of relying on legal jargon or terms that are defined by statutes or legal decisions.

Closing the investigation

Once a conclusion is reached about what occurred, the employer must take swift, appropriate action including but not limited to discipline, termination, warning or the conclusion of the investigation without action. It is usually a good idea to separate the investigation function from the task of deciding what to do with the results. Someone in human resources is much more likely than an outside investigator to understand the effects of particular remedial action in the workplace and to ensure that the company is treating cases of similar severity in a similar manner. For this reason, it may be beneficial to request that an outside investigator not make any specific recommendations in the initial report.

Once someone from human resources reviews the factual determinations of the investigation, the investigator can be questioned about any remedial actions that might be contemplated. Any documentation issued to close out the investigation, whether or not discipline is issued, should remind all parties that the company’s policy prohibits retaliation and any suspicions of retaliation should be reported and investigated promptly. It is also helpful at this stage to review the company’s applicable policies with everyone involved in the investigation.