Employers must properly raise their concerns with the person who is the subject of the complaint. This involves telling the employee that a complaint has been made, providing all relevant supporting information and letting them know that disciplinary action is a possibility.
As the employer you are to give the employee a reasonable opportunity to tell their side of the story, and genuinely consider the employee’s explanations (if they are provided).
In situations where the is an ongoing risk of further bullying taking place eg. the complainant and the subject employee work closely together, it is usually advisable to stand down the subject employee pending the outcome of a thorough investigation.