This involves advising the employee that you are undertaking an investigation, explaining the process of that investigation and the timelines that you estimate will be involved.
In most instances this will involve a fair and thorough investigation on what exactly happened. In more complicated matters this could involve interviewing multiple witnesses, gathering physical evidence and presenting it to the employee.
Before you can present it to the employee or before you can interview the employee you must give them written notice of your intention to hold such a meeting, the purpose of the meeting and what the outcome could be in the process in the event that the alleged behaviour was proven.
You must advise them in that letter that they are entitled to bring a support person to the disciplinary meeting, and they can take legal advice and bring a legal advisor if they choose to.
If after conducting an interview of the employee who is accused of breaching any duties to you should they introduce some new information that needs to be further investigated, you must do so first and then present that new information to the employee and ask for any further comment.
Once you have completed the investigation you can then make a decision and advise the employee and/or their legal advisor.
If the allegation is serious, it is sometimes advisable to engage the services of an Independent Workplace Investigator. It is important this person is qualified to undertake the task and there are a number of people now that specialise in these types of investigations.
Using an Independent Workplace Investigator avoids the allegation that the employer was biased in undertaking the investigation themselves.