Yes – in fact this is imperative to conducting a proper investigation.
If an accused is called into an interview by complete surprise, with no expectation of a problem, and then hit with a barrage of sensitive and difficult questions, their tone and posture will understandably be impacted. They may be nervous, defensive, confused, or any other range of emotions. This will come through both in their answers and their body language, and would then be used by investigators to wrongly judge their credibility.
A person accused of wrongdoing should not be surprised by their interview with a workplace investigator. While confidentiality is imperative outside of the investigation, the accused should be provided with details of the allegations against them so that they can adequately refresh their memory, and speak to the incidents in question without becoming confused, irritable, or flustered.