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If You Think It's Happening, It Probably Is
With 14 years of experience in law enforcement, SWAT operations, and military service, licensed private investigator Zach Wallis brings proven expertise to every case. His background includes serving as a Deputy Sheriff, Billings Police Officer, Field Training Officer, SWAT Sniper Team Leader, and Infantry Team Leader in the Montana Army National Guard. He has trained officers statewide and earned both the Medal of Valor and the Life Saving Award.
Today, Zach provides attorneys, businesses, and private clients across Montana with precise, discreet, and fact-driven investigative services. From complex criminal and civil cases to critical-incident and officer-involved shooting investigations, he delivers reliable results grounded in professionalism, integrity, and real operational experience.
Our Services
At Billings PI Services, we are dedicated to providing a wide range of investigative services, from legal assistance to infidelity cases and GPS tracking. Our commitment to excellence ensures high-quality results for every client. Our team of professionals is ready to assist you in all your investigative needs


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Whether you're dealing with a sensitive personal matter, workplace concerns, or just want to better understand behavioral cues, this free guide gives you clear, actionable steps used by trained investigators. It’s designed to help you make more confident, informed decisions.










