How do you conduct investigation interviews: order, rights, and technique?

The interview is where the planning that frames an investigation meets live evidence, and where most procedural-fairness challenges are won or lost. Work the order, the rights, and the technique deliberately.

Order of interviews. The common sequence is complainant first, then respondent, then witnesses — but no rule fixes it. The Canadian Human Rights Commission states plainly that “there is no single correct way to conduct an investigation,” and that some investigators begin with the principal party (complainant) while others begin with the responding party. The practical logic of complainant-first is that you cannot put precise allegations to the respondent until you know what they are: you interview the complainant to define the particulars, gather documents, then give the respondent the full case to answer, then test both accounts against witnesses. The AWI Guiding Principles treat order as a planning decision (“who will be interviewed, in what order, and for what purpose”), “subject to changes due to witness availability or new information.” Treat the sequence as a default, not dogma — and document why you departed if you do.

Putting the allegations to the respondent — the right to be heard in practice. This is the operational core of the “right to be heard” test set out in the procedural-fairness note. The respondent must receive the specific allegations — the conduct, approximate dates, and context — in enough detail to mount a meaningful response, ideally in writing and in advance of the interview. Canadian courts enforce this: in Geluch v. Rosedale Golf Assn. (2004) the court found the investigation unfair where the employer failed to interview the respondent to get their version. The respondent is entitled to the substance of the case, not every witness statement verbatim (Clarke v. Syncrude Canada Ltd., 2013 ABQB 252). The duty is ongoing: if contradictory evidence emerges later, the investigator must put it to the respondent for response — the Federal Court enforced this “right of reply” in Marentette v. Canada (Attorney General), 2024 FC 676, where a respondent was never shown the other side’s evidence. But fairness ends when the parties have had a full opportunity to answer; Carreau v. Canada (Attorney General), 2025 FC 1537 held that fairness does not require reopening the process for comment on the draft findings once that opportunity has been given. Seek specific admissions or denials on each allegation.

Support persons. Allowing a support person (a colleague or, in a unionized workplace, a union representative) is defensibility best practice and is contemplated by the AWI Guiding Principles and Ontario guidance — it is not a freestanding legal right in most non-union private workplaces. Note the limits: in Canada, employees generally have no inherent right to legal counsel in an internal interview (Honda Canada Inc. line of authority). A support person should not give evidence for the interviewee or coach them; their role is support, not advocacy. In unionized settings, collective-agreement representation rights govern.

Open, non-leading questions. The AWI Guiding Principle is that “beginning the interview with open-ended, non-leading questions is more likely to elicit probative information than closed-ended, leading questions,” followed by specific follow-ups. Ask the witness to recount events in their own words, then probe for detail. Ontario’s guidance frames it the same way: “When interviewing, ask specific questions about the incident or complaint. For example, what did the person see, hear or experience. Take detailed interview notes.” Do not ask the witness to guess. Leading interviews are a recognized failure mode, covered in the note on how investigations go wrong.

Reluctant or hostile witnesses. Reluctance should not stall the investigation. Reassure the witness that reprisal is prohibited and information is shared on a need-to-know basis. Where an employee refuses, employers can generally require participation as a condition of employment and may discipline for insubordination for refusal — but you cannot physically detain anyone, and refusal alone is not protected the way participation is. Document your reasonable efforts to engage non-cooperative witnesses (calls, emails, letters). With hostile or manipulative interviewees, the risk is that the witness seizes control of the interview; stay neutral, keep returning to the fact-finding purpose, and do not get drawn into a power struggle.

Contemporaneous notes and recording. Take detailed notes during every interview — date, time, location, who was present, breaks, and the questions you asked, not just the answers. Ontario’s Code of Practice expressly requires detailed interview notes. Rubin Thomlinson’s guidance is blunt: “Document, document, document,” and keep your notes after the report is written, because they are the contemporaneous record of thoroughness if the matter is litigated. Whether to audio-record is a genuine house-method divergence: some experienced investigators record routinely (with the interviewee’s consent, captured on the record) to ensure an accurate record; others rely on detailed notes and decline to record to protect confidentiality. There is no legal requirement to record. Pick a practice, apply it consistently, and disclose it up front.

For an Ontario SMB, the cheapest insurance is a written interview outline: a preamble covering purpose, confidentiality, and the anti-reprisal reminder; the specific allegations to put to the respondent in writing; open questions; and a notes template. The statutory duty that frames all of this — the OHSA “appropriate in the circumstances” standard and the harassment Code of Practice — lives in the compliance cluster, not here. This is general information, not legal advice.