To ensure a safe workplace and minimize costly disputes and crises, employers should swiftly investigate employee concerns as they arise.

In some states, including California, employers are legally obligated to promptly investigate employee complaints of harassment, discrimination, and retaliatory behavior.
Understanding the nuances and sensitivities that come with these types of claims can allow employers to make an informed decision about how to undertake an investigation to ensure legal compliance and resolution.
Internal vs. external investigator: Which is right for you?
A workplace investigation may be conducted by an employee (typically someone from human resources), or by an external investigator hired by the employer. In either case, the investigator should be knowledgeable about standard investigatory practices, either through training by a professional organization (e.g., SHRM, the Association of Workplace Investigators, etc.) or through prior experience conducting investigations.
Factors that should be considered in deciding whether to hire an external investigator include:
- The complexity and seriousness of the allegations.
- The likelihood the allegations will result in litigation.
- The risk of media scrutiny.
- Current workload of internal personnel.
- The complainant’s trust or distrust of the company.
- The nature of the allegations.
How to conduct an investigation
Importantly, the law requires employee complaints to be “promptly” investigated, whether internally or externally.
Investigations should be treated as a fact-finding exercise, where the investigator reaches a reasonable conclusion regarding whether the alleged wrongdoing is substantiated (i.e., whether it is more likely than not that the alleged wrongful conduct occurred). Investigators should not reach legal conclusions.
All investigations should begin with an analysis of the complaint and an interview of the complainant (if known) to determine the allegations. Once the scope of the investigation is determined, the investigator should begin interviewing witnesses one by one.
The investigator should begin each witness interview by:
Introducing themselves and thanking the witness for their time.
- Briefly explaining the investigation process, and making clear that their role is to ask questions, review relevant documents and summarize factual findings in a report.
- Explaining the importance of the witness providing truthful information.
- Informing the witness that retaliation violates the law.
- Asking the witness to refrain from recording the meeting (if virtual).
- Asking if the witness has any questions before you begin.
- Informing the witness that they can schedule an additional meeting, if necessary.
The substance of the witness interview should focus on the witness’ background and any information the witness has that is relevant to the investigation. The investigator should ask open-ended questions to elicit relevant information and avoid close-ended questions so as not to cause the witness to feel attacked. It is important for the investigator to operate as a fact-finder when interviewing witnesses — not an interrogator.
What should be included in a final report
After each witness interview, the investigator should review any documents provided by the witness and analyze whether any additional witnesses should be interviewed.
Once all witnesses have been interviewed and all relevant documents have been reviewed, the investigator should draft a final report that summarizes the investigation and states whether the allegations are substantiated. There are many ways the final report may be structured. One way is to include the following:
- Executive summary. Identify the investigator, summarize the allegations and state whether each allegation is substantiated.
- Scope of investigation. List the witnesses, their titles and their respective interview dates. List the key documents reviewed during the investigation and attach them as exhibits.
- Investigation observations and highlights. Tell a succinct, easy-to-read story of the relevant events based on witness testimony and relevant documents. Explain where an event (or nonoccurrence thereof) is unclear based on a he-said-she-said situation or otherwise. In the case of a he-said-she-said situation, it may be appropriate for the investigator to make a credibility determination.
- Conclusion. Briefly conclude whether each allegation is substantiated or unsubstantiated.
Final steps
After reviewing the investigator’s report, it is then up to the employer to decide what, if any, remedial measures to implement as a result.
Regardless of industry or company, employee complaints are inevitable. Having clear policies in place and providing management training can reduce workplace issues. Employers must be mindful of best practices and choose the right avenue to undergo claim investigations to achieve timely compliance while minimizing workplace disruption.