How to conduct an HR investigation: eight steps to compliance

Executive overview

When a harassment complaint lands on your desk, the law requires immediate action — there is no waiting until Monday. Employers are legally obligated to investigate complaints touching harassment, discrimination, retaliation, safety, and ethics under Title VII, the ADA, ADEA, OSHA, and Sarbanes-Oxley.

A good-faith review — impartial, diligent, and evidence-based — protects both parties and the organisation from costly litigation.

Failing to protect a complainant from retaliation, as in Burlington Northern v. White, can land an employer before the Supreme Court.

Legal trigger and confidentiality

• No formal complaint is required — HR must act on anything it knows or should have known about.
• Ensure confidentiality throughout; share information only on a need-to-know basis.
• Do not over-promise: witnesses will need to be interviewed, so some information will surface.

Selecting and preparing the investigator

• The investigator must be objective, have no stake in the outcome, and possess working knowledge of employment law.
• They must not be a direct colleague of either party.
• A third-party professional is often the best choice for unbiased, thorough review.
• If delegating, maintain regular update cadence with the assigned investigator.

Gathering evidence

• Collect emails, messages, documents, CCTV footage, and badge-swipe records as appropriate.
• Match evidence type to the allegation — not every category is relevant to every case.
• As an HR admin, you typically have access to email systems and can retrieve what is needed.
• Document everything; clear records are essential for fair outcomes and legal compliance.

Conducting interviews

• Interview the complainant, accused, and all relevant witnesses.
• Prepare questions in advance; use open-ended questions, not leading ones.
• Leading questions to avoid: "Did the accused threaten you?" or "Were you scared?"
• Preferred form: "Can you describe what happened?" or "What events led up to the incident?"
• Record interviews with consent and take detailed notes.

Analyzing findings and making a decision

• Look for consistencies and discrepancies across accounts.
• Apply the preponderance of evidence standard: more likely than not the conduct occurred.
• Corrective action ranges from training and mediation to termination, scaled to severity.
• A thorough employee handbook helps anchor fair, swift decisions.
• Communicate outcomes to all parties; document findings and actions in detail.

When to escalate to authorities

• Criminal conduct — money laundering, drug dealing, physical harm — requires immediate law enforcement contact.
• Do not attempt to handle criminal matters through internal investigation alone.

Lessons from Burlington Northern v. White

• Sheila White filed a sexual harassment complaint; the company retaliated with reassignment and a 37-day unpaid suspension.
• HR failed to protect her from retaliation and lacked thorough documentation and follow-up.
• The Supreme Court ruled in her favour, establishing that retaliation under Title VII is unlawful.
• The employer faced significant legal costs, damages, and reputational harm.