Please note that this is a general response that we send to all members having a Fact-Finding Meeting. Your situation may have additional needs.
What is a fact-Finding Meeting?
If you've been asked to attend a "fact-finding meeting" you should be prepared with a few things. The most important is that if you are the subject of the meeting, the employer may be following up on a complaint brought forward by someone else or are following up on a situation they have observed. The meeting is not disciplinary but it may lead to discipline based on the findings. You should bring a steward. If you are alone in the meeting, respectfully ask if the meeting can be rescheduled until a steward can attend with you. Managers will generally agree to this since it's in everyone's best interests that you have representation.
Be Succinct
During the meeting, be succinct in your answers. Don't elaborate or offer helpful additional information. ("I never looked in the confidential files on Monday. I did that on Friday.") Don't interpret what the manager means and add that to your response. Stick to the facts and only the facts. "It was afternoon." "The light was red." "I like chocolate." Also don't throw your coworkers under the bus. It won't change the outcome of what you did or the nature of the fact-finding mission. (Yes, we know "everybody" does it, but right now you're the subject and the facts are what will help.) If you remember something after the meeting, ask your steward what to do.
Stick to the facts
Stick to the facts and only the facts. If the manager asks you to consider how someone else felt or what could have happened, don't willingly go down that path unless it's specific to the investigation. What could have happened if Mr. Smith had woken up? We will never know because the fact is that he stayed asleep. Most of the time your steward will cut off this kind of speculative opinion-finding, but if you are helpfully answering everything quickly, it's a lot harder for the steward to halt that kind of questioning.
Ask for a caucus
If you are feeling overwhelmed, emotional, or just need guidance, ask your steward if you can caucus. That's very normal. If your steward has questions or sees you need help, they might ask for a caucus.
There's no handy tricks
Be aware that being evasive or trying to win on a technicality won't help you. This isn't a trial and the manager is trying to get your side of the story to get a full picture. If they perceive you as unhelpful, that's going to colour how they interpret their collected facts.
Paint a picture of what happened
Here is what you should focus on: if you didn't do the thing you're being accused of, state the facts and paint a picture of what really happened. If you did the thing you're being accused of, own it. The employer already did some pre-work before they came to you. Denying it happened won't help you.
Own it if you did it
In addition to owning it, consider how your actions impacted others and apologize. Don't just say sorry like it's a checkbox though. Sincerity is as important as owning it.
Remember that this is your chance to defend yourself. Use it well.