How to Conduct an Internal Investigation: A Step-by-Step Guide

Internal investigations start when an organization needs to look into alleged misconduct, compliance violations, fraud, harassment, or other workplace concerns. The quality of the investigation determines whether findings will hold up in legal proceedings. It also shapes whether the organization can show due diligence and whether the outcome will withstand scrutiny from regulators, courts, and the public.

Step 1: Assess the Situation and Determine Scope

Before any investigative action, assess several key factors:

• The nature and seriousness of the allegation
• Whether immediate protective action is required, such as separating subjects from evidence or from affected individuals
• Whether internal investigators can handle the matter or whether outside investigators are required
• Whether the investigation should be structured under attorney-client privilege

Outside investigators and outside legal counsel are strongly advisable for allegations involving executives or senior leadership, allegations with potential criminal dimensions, or matters that may result in significant litigation.

Step 2: Establish the Investigative Structure

Define who will conduct the investigation. For the investigation to be credible, the investigators must be genuinely independent from the subject. An HR investigation into a complaint against a manager's supervisor does not work if the HR department reports to that same executive.

Decide whether the investigation will be structured under attorney-client privilege or work-product protection. Communications between investigators and legal counsel may be protected from discovery. Documents prepared in anticipation of litigation may also be protected if the investigation is properly structured.

Define the scope: what allegations will be investigated, what evidence is relevant, and what questions the investigation will answer.

Step 3: Preserve Evidence

Evidence preservation is the highest-priority early action. Before subjects know about the investigation, preserve relevant documents, emails, financial records, electronic data, and any other information that subjects might alter or destroy.

This includes:

• Issuing a litigation hold to all relevant custodians
• Securing electronic devices that may contain evidence
• Preserving backups of relevant financial and accounting systems

Failure to preserve evidence can lead to spoliation findings in later litigation and regulatory proceedings. It can also make the investigation's findings easier to attack.

Step 4: Plan and Conduct Witness Interviews

Interview planning matters. The sequence should generally start with witnesses who have knowledge but are not subjects of the investigation. It should then move toward subjects after the investigative picture is clearer.

Each interview should be planned with a clear sense of what the witness likely knows and what the investigation needs from them. Take interview notes contemporaneously and document them. A detailed written record of each interview is essential in matters that may result in litigation or regulatory proceedings.

Subjects have rights. They should be told the nature of the investigation and that the interview is part of it. Instructions about confidentiality must be carefully calibrated. Courts have placed limits on blanket confidentiality instructions to witnesses in employment investigations.

Step 5: Analyze Evidence and Document Findings

Analysis means assessing all evidence gathered, identifying corroborating and contradicting information, evaluating witness credibility, and reaching conclusions the evidence supports. Findings should be grounded in the evidence and expressed with appropriate qualifications.

The investigation report should document:

• The scope and methodology
• The evidence reviewed
• The witnesses interviewed
• The findings

Write the report with awareness of who will read it. Courts, regulators, and boards all evaluate investigation reports, and the quality of the report affects the credibility of the findings.

Step 6: Remediation and Follow-Up

Investigation findings must be acted upon. Substantiated misconduct requires a response proportionate to the severity of the finding. The response should be documented and consistently applied.

Organizations that investigate misconduct and take no effective action have done something more damaging than not investigating. They have a record of having known about the problem.

Common Triggers and When to Escalate to Outside Investigators

Not every workplace complaint requires a full-scale investigation, and not every investigation requires outside professionals. The decision turns on several factors:

• The seniority of the subject
• The potential financial exposure
• The likelihood of regulatory or criminal involvement
• Whether an internal team can credibly claim independence

A mid-level harassment complaint with contained facts and a cooperative subject can often be handled by a trained HR professional. A complaint that names the CFO, that touches financial reporting, or that comes from a whistleblower protected by statute is a different matter.

Typical escalation triggers include:

• Allegations of financial fraud, bribery, or Foreign Corrupt Practices Act concerns
• Claims against officers, directors, or anyone in the reporting chain of the HR or compliance function
• Matters where regulators, law enforcement, or the media may become involved
• Any investigation where the organization expects its findings to be tested in court

In each of these scenarios, engaging independent investigators through outside counsel preserves both the substantive quality of the work and the procedural protections that make it defensible later. Our team regularly supports law firms in these situations, working under counsel's direction to gather facts that can be produced, explained, and defended.

Preserving Attorney-Client Privilege and Work Product

Privilege protection does not happen automatically because a lawyer is copied on an email. It requires deliberate structure. The investigation should be commissioned in writing by counsel, for the purpose of providing legal advice. Investigators should be retained either by counsel directly or through an engagement that explicitly references the legal purpose. Interview memoranda should be marked as privileged and confidential. Investigators should give appropriate Upjohn warnings to employee witnesses, making clear that counsel represents the organization and not the individual.

Privilege can be waived by accident. Several actions can destroy protection:

• Sharing draft reports with operational personnel who are not within the privilege
• Discussing interview content in internal meetings without appropriate controls
• Producing the report to a regulator without a non-waiver agreement

When the subject matter involves financial irregularities, the calculus becomes more complex. Auditors, regulators, and sometimes prosecutors may request the work. Organizations handling these matters should coordinate closely with counsel. Our certified fraud examiners are accustomed to operating within privilege structures while also producing work that can be selectively disclosed when strategy requires it.

Digital Evidence and Forensic Collection

Most modern internal investigations turn heavily on digital evidence: email, chat platforms, collaboration tools, mobile device content, cloud storage, and access logs. The manner in which this evidence is collected matters enormously. Self-collection by custodians is generally inappropriate in any matter that may result in litigation. It creates chain-of-custody gaps and offers the subject a chance to delete or alter responsive material. Forensically sound collection, performed by qualified examiners using validated tools, produces defensible images with documented hash values and preserved metadata.

A competent collection process addresses:

• Deleted files
• Cloud-resident data that may not be captured by a mailbox export
• Ephemeral messaging applications
• Personal devices used for business purposes

It also addresses authentication. An email produced in litigation is worth considerably more when its authenticity can be shown through forensic provenance rather than the custodian's testimony alone. Our digital forensics practice handles these collections for corporate and legal clients across the country. We routinely coordinate with e-discovery vendors to move responsive data into review platforms without compromising the underlying forensic integrity.

Due Diligence and Background Work Within the Investigation

Internal investigations frequently surface questions that reach beyond current employees and current transactions. A fraud inquiry may point toward a vendor whose legitimacy was never tested. A harassment investigation may reveal that a senior hire had a pattern of similar conduct at previous employers that a thorough pre-hire check would have caught. A kickback allegation may implicate a family member or undisclosed business relationship that only appears through public records work.

Treating the investigation as a chance to close these information gaps strengthens both the immediate findings and the organization's future posture. Several workstreams extend the analytical value of the work:

• Background investigations on relevant third parties
• Corporate record research on vendors and counterparties
• Asset or relationship mapping for subjects of financial inquiries

We provide background investigations and due diligence in support of internal investigations. In many engagements these workstreams run in parallel with the interview and document review phases rather than afterward.

Communications, Confidentiality, and Legal Constraints

Managing information flow during an investigation is its own discipline. Too tight a grip invites accusations of coverup. Excessive disclosure can taint witness recollections, expose the organization to defamation risk, and derail parallel law enforcement processes. The National Labor Relations Board and state regulators have reviewed confidentiality instructions to employee witnesses. Blanket demands that employees discuss nothing with anyone are increasingly difficult to defend. Instructions should be tailored to the specific investigation and should explain the reason for confidentiality where it is appropriate.

External communications require particular care. Statements to employees, customers, regulators, and the press should be coordinated through counsel and grounded in facts the investigation has actually established. Premature public commitments to outcomes, or public criticism of individuals before findings are complete, create exposure that well-run investigations otherwise avoid.

Our corporate investigation team conducts independent internal investigations for organizations, boards, and legal counsel. Corporate clients engage us directly for workplace and compliance inquiries, and our certified fraud examiners handle the forensic-accounting work when the subject matter is financial. Contact us for a confidential consultation.