This document describes the roles and responsibilities of Investigators in the K-12 space. It was created to reflect the changes made by the U.S. Department of Education in the Final Rule regulations, which went into effect August 14, 2020. This document is intended for use by anyone who wishes to assess and ensure compliance with Title IX (e.g., Investigators, district and state Title IX compliance officers, policy makers, and Title IX Coordinators). "Investigator Roles and Responsibilities" is part of the "Title IX 2020 Regulations" series. This series examines the overall impact of the Title IX 2020 regulations and its specific impact on various positions. See: "Title IX Coordinator Roles and Responsibilities" [ED627900], "Title IX then and Now for K-12--What has Changed?" [ED627904], "Title IX Decision-Maker Roles and Responsibilities" [ED627894], and "Title IX Grievance Procedure" [ED627901].