As a former employment litigator, I’ve had a unique opportunity to observe how California employers handle internal workplace investigations. While some manage them well, many do not.
Through my experience, I noticed that poorly handled investigations often share common traits — mistakes that could have easily been avoided with proper guidance. Below are some of the most common errors employers make during workplace investigations, which often lead to costly legal consequences.
1. Failing to Investigate or Delaying an Investigation
Many employers overlook complaints that don’t explicitly claim harassment or discrimination. However, complaints that hint at preferential or unequal treatment may escalate into formal discrimination claims if ignored.
Employers must investigate promptly — even if no formal complaint has been filed. Similarly, delaying an investigation can lead to liability. Managers often receive informal complaints from employees who wish to remain anonymous. If these concerns aren’t properly addressed, employers could be held liable for failing to prevent potential harassment or discrimination.
Tip: Managers should always consult with HR when handling reluctant complainants to determine the best course of action.
2. Lack of Thoroughness: Failing to Interview Key Witnesses or Gather Critical Evidence
A frequent pitfall is failing to conduct a thorough investigation. Some investigations neglect to interview key witnesses — including the subject of the complaint — or ignore third-party witnesses and documentary evidence for the sake of expediency, at best, or the sake of arriving at a predetermined finding, at worst. For example, courts have found that a poorly conducted investigation where key witnesses were not interviewed could potentially be interpreted as designed to ignore evidence that could refute an allegation for the purposes of supporting a termination of employment. Such an investigation could support a finding of actual malice against the employer as well as an award of punitive damages. ( King v. U.S. Bank, 53 Cal. App. 5th 675, (2020)).
Therefore, it is important that all investigations be thorough. Potential sources of documentary evidence include:
Emails
Text messages
Photos
Internal security footage or logs
Personal journals, notes
Failing to interview all potential witnesses or gathering relevant documentary evidence makes the investigation vulnerable to challenges and can lead to incomplete or biased conclusions.
Tip: Interview all relevant witnesses and gather all critical evidence to ensure a fair and defensible investigation.
3. Failing to Evaluate Credibility Where Evidence Conflicts
Internal investigations often fail to assess witness credibility in “he said/she said” situations. Some reports accept one party’s account without explaining why opposing accounts were dismissed.
Credibility assessments are essential to producing findings that withstand scrutiny. Key factors to consider when evaluating credibility include:
Inherent plausibility of a witness’s story
Corroboration by other witnesses or evidence
Opportunity and capacity to observe
Internal consistency of the witness’s statements
Bias
Motive to lie
Past conduct or pattern of behavior
Tip: Thoroughly document credibility assessments to strengthen the investigation’s conclusions and defend against accusations of bias or incompleteness.
4. Failing to Thoroughly Document the Investigation
Documentation is critical. Failing to document interviews, evidence, findings, and decisions can severely undermine an investigation if later challenged.
Inadequate documentation makes it difficult for employers to demonstrate that the investigation was conducted fairly and in good faith.
Tip: Maintain detailed and accessible records of every step of the investigation, including summaries of interviews, evidence reviewed, and final conclusions.
5. Writing a Substandard Investigative Report
A clear, detailed investigative report is vital to defending employment decisions based on the investigation.
A poorly written report — one that lacks clarity, omits critical findings, or fails to address conflicting evidence — can compromise both the investigation and any subsequent employment actions.
Tip: A strong investigative report should:
Clearly outline the steps taken during the investigation
Summarize evidence collected
Analyze conflicting evidence
Make factual findings
Present clear, reasoned conclusions
Without this, employers face significant challenges defending their decisions if they are later scrutinized.
Conclusion
By avoiding these common mistakes and following best practices, employers can better protect themselves from legal exposure, improve the quality of their investigations, and foster trust with employees.
Thorough, impartial, and well-documented investigations are the key to resolving workplace issues fairly and efficiently.