What type of investigation does a civilian employee in a critical-sensitive position needs?

A civilian employee in a critical-sensitive position typically requires a background investigation known as a "Top Secret" security clearance. This investigation assesses the individual's loyalty, reliability, and trustworthiness, including a review of personal history, financial records, and any potential criminal activity. The process may involve interviews with the individual, references, and checks with law enforcement and other agencies to ensure the candidate can handle sensitive information responsibly. Regular reinvestigations are also conducted to maintain the security clearance.