Sonja Arndt‑Johnson is a Special Counsel at Buchalter and a core member of its Privacy & Data Security and White Collar & Investigations practice groups. She is a trusted advisor to companies, executives, and individuals navigating high-stakes government investigations, criminal exposure, and complex civil fraud disputes—delivering swift, strategic solutions that protect reputation, liberty, and enterprise value.
Ms. Arndt‑Johnson brings a unique combination of prosecutorial experience and sophisticated private practice, enabling her to anticipate government strategy and defend clients with precision in their most consequential matters. Prior to private practice, she served at the U.S. Department of Justice in Washington, D.C., including the U.S. Attorney’s Office for the District of Columbia, the Office of International Affairs, and the Computer Crime and Intellectual Property Section (CCIPS). She also served as a prosecutor in the Santa Clara County District Attorney’s Office.
She represents corporations, executives, and individuals in sensitive criminal investigations, fraud indictments, and parallel civil enforcement actions involving agencies such as the DOJ, SEC, FTC, IRS, Department of Defense, and California Attorney General, as well as international investigative bodies. Known for her decisive and discreet approach, she conducts high-stakes internal investigations, guides clients through government inquiries and charging decisions, and develops aggressive defense strategies in matters involving fraud, money laundering, RICO, and qui tam allegations.