A Manager is an Investigator with the ability to create Managers, Investigators, or Viewers within your organization. They can view all Candidates in the system and view reports that reflect all organizational information. They can monitor the progress of all Investigations or just those assigned to them. If you have only one Investigator in your organization they must be a Manager.

If you want all Investigators to have the Manager role, that's fine and may be more conducive to an organization where multiple Investigators may work on multiple cases with minimum "ownership" of the case by the Investigator.