Dianna Strain is a former FBI Special Agent with more than 22 years of experience specializing in crime scene investigations, violent crimes, terrorism, crimes against children, and forensic evidence. Her career includes extensive work on major criminal investigations involving homicides, mass shootings, kidnappings, terrorism-related matters, and complex forensic evidence issues.

As Senior Team Leader of the Dallas FBI Evidence Response Team, Dianna led investigative and forensic response efforts in serious, high-stakes matters requiring precision, discipline, and defensible documentation. Her background gives Principled Investigations Group a significant forensic and investigative advantage in cases where evidence handling, reconstruction, and expert analysis are critical.

Today, Dianna is a Licensed Private Investigator and Senior Adjunct Professor at Abilene Christian University. She provides expert consultation and testimony in criminal defense, forensic evidence matters, CSAM-related cases, violent crime investigations, and complex case reconstruction.