Complex sentence: Cerberus Action also known as "Operation Cerebus" was the code-name for a two-year multi-agency investigation of cultural and archaeological artifact theft in the Four Corners region of the United States, where Colorado, Utah, Arizona, and New Mexico converge.
Split into simpler sentences: Cerberus Action also known as "Operation Cerebus" was the code-name for a two-year multi-agency investigation of cultural and archaeological artifact theft in the Four Corners area. It is now known as the Four Corners where Colorado, Utah, Arizona, and New Mexico converge.