Dear Sheetal,
Congratulations on joining the banking sector. You wish to conduct the "employee investigation". However, what is the purpose? Is it because of the fraud?
By the way, the focus of any type of investigation should be on the incident and not on the person. You should investigate what has happened but rather who has done it. If you focus on a person, it could cloud your mind and no enquiry or investigation should be conducted with prejudice.
Once the misconduct of grave nature or fraud comes to light, identify how it surfaced and then make a rough chronological sketch of it. Thereafter, start investigating how things went wrong.
While investigating to find out whether there was a failure of the system but we are blaming people. Because of the improper systems and processes, many times the mishap waits to happen. However, after the mishap, the blame is pinned on the individual.
Thanks,
Dinesh Divekar