About Us

At Astria SI, we provide professional, discreet, and results-driven investigative services grounded in decades of federal law enforcement experience. Based in Sioux Falls, South Dakota, we operate with the values that define our community — integrity, hard work, and respect. These principles guide everything we do, whether we're serving local clients or working with legal and corporate teams across the country.

Our founder brings a distinguished background in complex investigations, risk assessment, and interagency coordination — skills developed over a long career at the highest levels of public service. That experience, combined with a strong Midwestern ethic, means clients can count on us for clear communication, ethical conduct, and a relentless focus on results.

We support legal professionals, corporate clients, and individuals who need trusted intelligence, reliable documentation, and clear insight. Whether you're navigating a high-stakes legal case, conducting internal due diligence, or managing personal risk, we bring clarity to complexity — and confidence to your next move.

What sets us apart:

  • Proven Investigative Expertise: Our methods are informed by years of hands-on experience across criminal, civil, and corporate investigations.

  • Discretion & Professionalism: Every case is handled with confidentiality, respect, and ethical integrity.

  • Strategic Insight: We provide not only facts, but actionable context and clear guidance.

  • Seamless Collaboration: We work effectively with law firms, businesses, and law enforcement to support outcomes and streamline communication.

At the core of our work is a simple principle: the truth matters — and finding it requires experience, precision, and trust. That’s what we deliver.

Meet Rob Mertz

Robert (Rob) Mertz

Founder & Lead Investigator | Astria Security & Investigations LLC

As the founder of Astria Security & Investigations LLC, Robert (Rob) Mertz brings over 20 years of federal law enforcement experience, with a focus on high-stakes investigations and executive protection. A retired FBI Special Agent, Rob has a proven track record in handling complex criminal investigations, including those involving white-collar crimes, violent crimes, narcotics, human trafficking, and many more.

Rob’s career in the FBI began in 2002, and for more than two decades, he dedicated himself to solving major federal criminal cases, primarily under the Major Crimes Act within federally recognized Native American reservations. Throughout his career, Rob managed high-profile investigations, including coordinating multi-agency task forces, leading arrest and search warrant teams, and conducting thousands of interviews with witnesses, victims, and suspects.

A seasoned expert in executive protection, Rob has developed a keen understanding of the security needs of high-net-worth individuals, offering specialized protection services that include route planning, logistical coordination, and crisis management to ensure client safety at all times. His background in managing and mitigating high-risk situations makes him uniquely qualified to offer unparalleled protection and peace of mind.

Rob's exceptional communication skills, meticulous attention to detail, and ability to manage complex cases through to resolution have earned him numerous accolades throughout his career. He is highly regarded by his colleagues, clients, and law enforcement partners for his integrity, dedication, and commitment to the highest standards of service.

Throughout his distinguished career, Rob has been involved in various high-impact roles, including as a FBI Special Agent Bomb Technician, Firearms Instructor, Seattle SWAT Team Member, and Maritime Liaison Agent. He led the Head Waters Safe Trails Task Force (HSTTF) and created the Seattle Pacific Area Maritime (SPAM) Fusion Team to enhance national security efforts. Rob's diverse skill set, extensive training, and leadership in the field make him a trusted and highly effective partner in security and investigations.

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