SAC Riddle began his civilian law enforcement career in 1999 as a Police Officer in Texas, serving for six years. He began his ATF career in 2005, in the Fort Worth, Texas, Field Office. In 2013, he became the Resident Agent in Charge of the Cheyenne, Wyoming, Field Office. In 2017 he was assigned as a Program Manager in the Internal Affairs Division, Office of Professional Responsibility and Security Operations, which reviews and impartially investigates complaints and allegations of administrative or criminal misconduct or other integrity violations (including sexual harassment or racial discrimination) involving ATF personnel. SAC Riddle then served as an Assistant Special Agent in Charge (ASAC) for the Phoenix Field Division, a position he held from January 2020 to February 2024.