Start by understanding what you are actually dealing with

When someone goes quiet, gives one-word answers, or refuses outright to engage, it is tempting to read it as defiance. In practice, reluctance during an investigation usually comes from somewhere more understandable: fear about the outcome, distrust of the process, a belief that the decision has already been made, or simply not knowing what is expected of them. None of that excuses non-cooperation, and it does not remove their obligations. But it should shape how you respond. An investigator who assumes bad faith tends to find more of it.

It is also worth separating wilful non-cooperation from someone who is distressed, unwell, or struggling to follow what is being asked. Test that possibility early, and adjust your approach if it applies. A person who cannot engage needs support; a person who will not engage needs a clear, documented process.

Set expectations early and in plain language

Most difficulties are prevented rather than managed. Before any interview or request for information, make sure the person knows exactly what is happening and what is expected of them.

• Describe the purpose of the investigation in neutral terms — establishing facts, not reaching a verdict.
• Be specific about what you need: documents, a written statement, attendance at a meeting, answers to particular questions.
• Confirm the practical details: date, time, location, who will be present, and roughly how long it will take.
• Explain that cooperation is an expectation of their employment, and that a refusal will be recorded and may be addressed separately.
• Signpost support — a trade union representative, a colleague, occupational health, or an employee assistance programme.

Confirm it all in writing. A short email setting out the arrangements is far easier to rely on months later than a recollection of a conversation by the kettle.

Keep your own conduct beyond reproach

You cannot control how someone else behaves, but you can control whether your process looks fair. That matters both to the individual and to anyone reviewing your decision later.

• Stay calm and even in tone, even when the other person is not.
• Ask open questions once, then allow silence. Rushing to fill a pause often produces the confrontation you were hoping to avoid.
• Do not argue, bargain, or make promises about outcomes.
• Avoid sarcasm, threats, or references to consequences in the moment — those belong in a separate, considered process.
• If the meeting becomes heated, pause it and reconvene. Ending a difficult interview early is almost always better than letting it deteriorate.

If the person asks for a reasonable adjustment — a different room, the questions in advance, a companion — consider it seriously. Refusing a sensible request weakens your position and hands them a genuine grievance.

Record refusals precisely and without editorialising

When someone will not cooperate, write it down the same day, while it is fresh. Good records are factual, specific and free of your own interpretation of their motives.

• Note the date, time and who was present.
• Record the question or request as it was put, ideally word for word.
• Record the response as it was given, again as closely as possible, and note any silence or refusal to answer.
• Avoid words like "aggressive" or "evasive" unless you can describe the behaviour that led you to them.
• Confirm the record with anyone else who was in the room.

Keep a clear note, too, of what you told them about the consequences of refusing. If you never explained it, that gap will be noticed.

Escalate proportionately rather than punitively

Non-cooperation is a separate issue from whatever prompted the investigation, and it should be handled separately. A refusal to attend an interview is not evidence of the underlying allegation, and treating it as such is a common and damaging mistake.

Where cooperation is genuinely withheld, escalate in steps. First, restate the request in writing and give a clear deadline. Second, involve the person's manager or HR to reinforce the expectation. Third, if the refusal continues, refer it through your disciplinary or capability procedure as a distinct matter, with its own meeting and its own right of appeal.

Proportionality matters. A single missed meeting with a reasonable explanation does not warrant a formal process. A sustained, documented refusal to engage does.

Protect the process and the person over the longer term

Investigations end, but working relationships continue. How you handle a difficult participant will shape whether they re-engage once the matter is closed.

Be willing to revisit. People often become more forthcoming after they have had time to take advice, or once they understand that the process is genuinely impartial. Offer a further opportunity to respond, and record that you did. It costs little, and it strengthens both your findings and your credibility.

Finally, keep the circle tight. Discuss the individual's non-cooperation only with those who need to know. Being talked about is often the reason someone stopped cooperating in the first place — and it is the surest way to ensure they never start again.