When a workplace investigation is needed
Not every workplace issue requires a formal investigation, but many of the most serious situations do. Getting the investigation right is critical because it forms the foundation for any subsequent disciplinary or grievance outcome. If the investigation is flawed, any decision based on it is likely to be found unfair at tribunal.
You should consider a formal investigation when:
- An allegation of misconduct or gross misconduct is raised against an employee
- An employee submits a formal grievance
- A complaint of bullying or harassment is made
- A whistleblowing disclosure is received
- There is a suspected breach of company policy, such as fraud, data misuse, or health and safety violations
- An incident occurs that requires fact-finding before any management action
The purpose of the investigation is to establish the facts. It is not to prove guilt or build a case for dismissal. That distinction is fundamental, and losing sight of it is one of the most common reasons investigations are criticised at tribunal.
Appointing an impartial investigator
The person conducting the investigation must be impartial. They should have no prior involvement in the matter, no personal relationship with the parties that could create bias, and no conflict of interest.
In larger organisations, this might be an HR professional or a manager from a different department. In smaller businesses, finding someone completely unconnected can be difficult. If no suitable internal person is available, consider appointing an external investigator. This is particularly advisable in cases involving senior staff, complex allegations, or situations where the perception of fairness is especially important.
Whoever you appoint should have the skills and experience to conduct a thorough and fair investigation. This means understanding the principles of natural justice, knowing how to interview effectively, and being able to assess evidence objectively.
Where the investigation relates to a disciplinary matter, the investigator should ideally not be the same person who chairs the disciplinary hearing or makes the final decision. Separating these roles strengthens the fairness of the overall process. In small businesses where this is not practical, document why the same person performed both roles and demonstrate that the hearing was approached with an open mind.
Planning the investigation
Before you start interviewing anyone, plan the investigation properly. A well-structured investigation is more likely to be thorough, fair, and defensible.
Define the scope
Set out clearly what the investigation will cover. What are the specific allegations or concerns? What questions need to be answered? Defining the scope prevents the investigation from drifting into unrelated issues and helps keep it focused and proportionate.
Set a timeline
Investigations should be completed without unreasonable delay. Delay is unfair to all parties, particularly if the subject of the investigation has been suspended. Set a target timeframe at the outset and communicate it to the relevant parties. If the investigation takes longer than expected, explain why and keep people informed.
Write terms of reference
For more complex investigations, draft formal terms of reference. This document sets out the scope, the allegations being investigated, the investigator's remit, the expected timeline, and who will receive the investigation report. It provides a clear framework and helps manage expectations.
Identify evidence sources
Before you begin, consider what evidence might be relevant:
- Documents such as contracts, policies, emails, letters, or reports
- Electronic records including system logs, access records, and chat messages
- Physical evidence
- CCTV footage (subject to data protection requirements)
- Witness testimony from colleagues, managers, or external parties
Make a list of potential witnesses and prioritise them based on relevance.
Gathering evidence
Collect documentary and physical evidence early in the process, before interviewing witnesses. This ensures you have the full picture before you start asking questions and reduces the risk of evidence being lost, altered, or destroyed.
Documents and records. Request copies of relevant emails, files, policies, and records. If the investigation involves potential fraud or data misuse, secure electronic evidence promptly. Involve your IT team if necessary to preserve data.
CCTV footage. If your workplace has CCTV and the footage is relevant, review and retain it as soon as possible. Most CCTV systems overwrite footage after a set period, so delays can mean losing key evidence. Ensure you handle the footage in line with your data protection obligations.
Physical evidence. If relevant, photograph or secure any physical evidence such as damaged property, equipment, or materials.
Data protection. Be mindful of your obligations under UK GDPR when collecting and processing personal data during an investigation. Only access information that is relevant and proportionate. Inform individuals about how their data will be used. Keep investigation records secure and retain them only for as long as necessary.
Interviewing witnesses
Witness interviews are usually the most important part of the investigation. How you conduct them directly affects the quality and credibility of your findings.
Preparing for interviews
- Notify witnesses in advance. Give them reasonable notice and explain the purpose of the interview. They are not obliged to attend but should understand the importance of co-operating.
- Prepare questions. Draft a list of questions based on the evidence you have gathered. Use open questions that encourage detailed responses rather than leading questions that suggest the answer you expect.
- Arrange a suitable location. The interview should be conducted in a private, comfortable setting. If the witness is working remotely, a video call is acceptable, but ensure confidentiality.
Conducting interviews
- Explain the process. At the start of each interview, explain the purpose of the investigation, that the interview is confidential, and what will happen with the information provided.
- Ask open questions. "What happened?" and "What did you see?" are more useful than "Did you see X do Y?" Avoid putting words in the witness's mouth.
- Listen carefully. Let the witness give their account in their own words. Follow up on key points but avoid interrupting.
- Take detailed notes. Record the interview as accurately as possible. If you use a note-taker, they should focus solely on recording the conversation. Audio recording is an option but requires the witness's consent and should be addressed in your investigation policy.
- Ask the witness to review the notes. After the interview, give the witness an opportunity to read the notes, make corrections, and sign them. This strengthens the reliability of the evidence.
Interviewing the subject
The person who is the subject of the allegation must be interviewed during the investigation. This is a fundamental requirement of fairness. They should be told the nature of the allegations, shown any evidence you intend to rely on, and given a genuine opportunity to respond.
The subject is entitled to be accompanied at an investigation meeting, particularly if it forms part of a formal process. They should be treated with respect throughout, regardless of the nature of the allegations.
Maintaining confidentiality
Confidentiality is essential throughout the investigation. Breaches of confidentiality can undermine the process, damage relationships, and expose your business to claims of unfair treatment or data protection breaches.
Inform all participants that the investigation is confidential and that they must not discuss the details with colleagues. Explain the consequences of breaching confidentiality. Store investigation records securely and restrict access to those who need to see them.
That said, absolute confidentiality cannot always be guaranteed, particularly if the matter proceeds to a disciplinary hearing where evidence must be disclosed. Be honest with participants about this limitation.
Writing the investigation report
The investigation report is the formal record of your findings. It should be clear, factual, and well-organised. A good report will:
Summarise the allegations. Set out what was alleged and against whom.
Describe the evidence gathered. List the documents reviewed, witnesses interviewed, and any other evidence considered. Attach copies as appendices.
Set out the findings of fact. Based on the evidence, explain what you have concluded happened. Where witness accounts conflict, assess their credibility and explain your reasoning. You are assessing the facts on the balance of probabilities, not the criminal standard of beyond reasonable doubt.
Separate facts from opinions. The report should focus on what the evidence shows, not what the investigator believes should happen next. The decision about disciplinary action is for the decision-maker at the subsequent hearing, not the investigator.
Make recommendations (if appropriate). In some organisations, the investigator is asked to recommend whether there is a case to answer. If so, the recommendation should be based solely on whether the evidence is sufficient to warrant a formal hearing.
Handing over to the disciplinary or grievance panel
Once the report is complete, hand it over to the manager who will chair the disciplinary hearing or grievance meeting. The investigator should be available to present their findings and answer questions but should not influence the decision.
The employee who is subject to the process must receive a copy of the investigation report and supporting evidence in advance of the hearing, with enough time to prepare their response.
Common pitfalls to avoid
Bias. The investigator must approach the process with an open mind. If they have a pre-existing view about the outcome, the investigation is compromised. Choose an investigator who can genuinely be impartial.
Unreasonable delays. Investigations should be completed promptly. Delays cause unnecessary stress for all parties and can undermine the process at tribunal. If the investigation is complex, communicate realistic timescales and provide regular updates.
Not separating investigation from decision. The investigation establishes the facts. The disciplinary or grievance panel makes the decision. Mixing these roles creates the appearance of unfairness, even if the outcome was reasonable.
Leading witnesses. Questions should be open and exploratory, not designed to confirm a predetermined version of events. Leading questions undermine the credibility of the evidence.
Failing to interview the subject. Every person accused of wrongdoing must have the opportunity to give their account during the investigation. Proceeding without their input is a serious procedural failing.
Poor record-keeping. If your investigation records are incomplete or disorganised, your ability to defend the process at tribunal is significantly weakened. Document everything as you go.
Ignoring relevant evidence. An investigation must be balanced. If evidence exists that supports the subject's account, you must consider it and include it in your report. Cherry-picking evidence that supports only one side is a hallmark of an unfair process.
How Rebox HR can help
We support employers through workplace investigations of all types, from straightforward disciplinary enquiries to complex multi-party complaints involving grievances, bullying, or whistleblowing. We can act as an external investigator to ensure impartiality, or advise your internal team on the correct approach.
If you are facing a situation that requires investigation and want to make sure the process is handled fairly and thoroughly, book a free consultation. Whether you need ongoing retained HR support or one-off project support, we will help you protect your business and your people.
