The experts that make up the SIGMA team have decades of experience assessing thousands of threats from careers in federal, state, and local law enforcement, education, criminal justice, mental health, and the law.  The work of SIGMA team members in threat assessment research and practice has helped define best practices in behavioral threat assessment and is cited as a model in U.S. national standards and federal guides.


Marisa R. Randazzo, Ph.D.
Managing Partner

Expert Marisa RandazzoDr. Randazzo is a Managing Partner of SIGMA and an international expert on threat assessment, targeted violence, and violence prevention.  Before joining the private sector, Dr. Randazzo served for ten years with the U.S. Secret Service, most recently as the agency’s Chief Research Psychologist.  She is co-author of The Handbook for Campus Threat Assessment and Management Teams (2008) and lead author of Implementing Behavioral Threat Assessment on Campus: A Virginia Tech Demonstration Project (2009).  Dr. Randazzo has been interviewed by an array of major television, radio, and print news outlets, including 60 Minutes, Nightline, Good Morning America, the Today Show, the Early Show, 48 Hours, Dateline NBC, MSNBC, the New York Times, and National Public Radio.  For Dr. Randazzo’s full bio, please click here.


Gene Deisinger, Ph.D.
Managing Partner

Expert Gene DeisingerGene Deisinger, Ph.D. is a Managing Partner of SIGMA and also serves as the Threat Management Consultant for the Virginia Center for School and Campus Safety  He is a licensed psychologist, certified health service provider in psychology, and a certified law enforcement officer.  Dr. Deisinger developed the threat management program and served as the primary threat manager for Iowa State University from the team’s inception in 1994 until 2009 when he was recruited to Virginia Tech as Deputy Chief of Police & Director of Threat Management Services, a position he held until his retirement in November, 2014. Dr. Deisinger has managed cases, and provided consultation and training for a broad range of governmental agencies, schools, campuses, government agencies, and other workplaces.  Dr. Deisinger is lead author of The Handbook for Campus Threat Assessment & Management Teams and has served as a subject matter expert for several professional and governmental initiatives related to enhancing safety in a broad range of organizations. He has been featured in Nature – International Weekly Journal of Science, the American Psychological Association Monitor on Psychology and the PBS Special, The Path to Violence. For Dr. Deisinger’s full bio,please click here.


William Modzeleski
Senior Consultant

Expert William ModzeleskiWilliam “Bill” Modzeleski is a Senior Consultant with SIGMA Threat Management Associates and a nationally recognized leader in the area of school safety and emergency management. Mr. Modzeleski is a former Associate Assistant Deputy Secretary of the U.S. Department of Education’s Office of Safe and Drug Free Schools. During his tenure at the Department of Education Mr. Modzeleski was instrumental in the development and implementation of several programs related to emergency management and violence prevention, including the Safe Schools/Healthy Students Program; School Emergency Response to Violence; and the REMS program.  Mr. Modzeleski served as co-author with staff from U.S. Secret Service on the Safe School Initiative, and co-author with staff from Secret Service and FBI on study on Targeted Attacks at Institutions of Higher Education.  For Mr. Modzeleski’s full bio, please click here.


Jeffrey J. Nolan, Esq.
Senior Consultant

Expert Jeffrey NolanJeff Nolan is a Senior Consultant in collaboration with SIGMA, a practicing attorney, and Chair of the Higher Education Practice Group at Dinse, Knapp & McAndrew, P.C.  Mr. Nolan specializes in employment law as well as on legal issues affecting colleges and universities.  Mr. Nolan is featured in several national lists of leading lawyers in employment and labor law.  He also served as a subject matter expert and faculty member for the national campus threat assessment training sponsored by the U.S.  Department of Justice, Office of Community Oriented Policing (COPS  Office).  For Mr. Nolan’s full bio, please click here.




Andrew S. Patrick
Senior Consultant

Expert Andrew PatrickAndy Patrick is a Senior Consultant with SIGMA, a Representative with the South Carolina House of Representatives, and a former Special Agent with the U.S. Secret Service.  Mr. Patrick has extensive experience conducting and supervising threat assessment investigations into threats against the President, First Lady, and other public officials, and in conducting criminal investigations into counterfeiting, financial institution fraud, identity theft, and computer fraud.  He is a licensed private investigator and CEO of Advance Point Global.  For Mr. Patrick’s full bio, please click here.




Jeffrey W. Pollard, Ph.D., ABPP
Senior Consulting Psychologist

Expert Jeffery PollardDr. Jeff Pollard is the Senior Consulting Psychologist with SIGMA, a Board Certified Licensed Psychologist, and founding member of George Mason University’s Threat Assessment Team, where he is Adjunct Faculty in the Department of Criminology, Law and Society.  He has consulted to universities, colleges, private individuals, and government agencies throughout the country on threat assessment.  One of Dr. Pollard’s current projects is with the Virginia Tech Victims Family Outreach Foundation in establishing a national standard for campus safety. He serves as a member of the Advisory Council for the 32 National Campus Safety Initiative and on the Advisory Board for the Consortium for the Advancement of Threat Assessment and Management in Higher Education. For Dr. Pollard’s full bio, .please click here.



Peter Romary, GKMA; LLB, JD
Senior Consultant

Expert Peter RomaryPeter Romary is a Senior Consultant in collaboration with SIGMA; an attorney licensed to practice law in North Carolina, the District of Columbia, and before the U.S. Supreme Court; and, a Certified Arbitrator and Mediator.  In his practice, Mr. Romary has concentrated on civil and criminal litigation, alternative dispute resolution, risk management, and on pro bono representation of over 100 victims of violence per year.  He now serves as Director of Student Legal Services and Adjunct Lecturer at East Carolina University.  Mr. Romary is the recipient of numerous honors, including a Knighthood and the Ellis Island Medal of Honor (the highest civilian honor sanctioned by Congress).  For Mr. Romary’s full bio, please click here.


Dorian Van Horn

Senior Consultant

Expert Dorian Van HornDorian Van Horn is a Senior Consultant with SIGMA Threat Management Associates and a nationally recognized leader in threat assessment and threat management.  Before joining the private sector, Ms. Van Horn served over 25 years as a Special Agent with the Naval Criminal Investigative Service (NCIS).  Ms Van Horn developed and was the NCIS Division Chief in charge of the Threat Management Unit and the Insider Threat Program.  She also oversaw the NCIS Family and Sexual Violence Program, and was responsible for the Death, Violent Crime, and the Cold Case Homicide Unit.  Ms. Van Horn was appointed by the Secretary of Defense as a Government Advisor to the Defense Science Board Task Force on Predicting Violent Behavior. For Ms. Van Dorn’s full bio, please click here.


Richard M. Wilson, CPP
Senior Consultant

Expert Richard WilsonRich Wilson is a Senior Consultant with SIGMA and a nationally recognized leader in the profession of threat assessment.  Mr. Wilson is a former Assistant Chief of Police with the Arizona State University (ASU) Police Department, serving a community of over 72,000 students across four campuses.  During his 25 years of campus law enforcement experience, he distinguished himself as one of the earliest practitioners of behavioral threat assessment in higher education and has over 16 years experience in case management and team training.  He also served as a crisis negotiation team leader.  Mr. Wilson is a Certified Protection Professional and has extensive experience in event security planning, to include numerous Super Bowl games, summer and winter Olympics games, NCAA Men’s Basketball Tournament, and numerous Presidential and dignitary protection details.  For Mr. Wilson’s full bio, please click here.


Denise Wolf, MA
Organizational Dynamics Consultant

Expert Denise WolfDenise Wolf is an Organizational Dynamics Consultant with SIGMA.  She has worked with a variety of companies in a number of industries, ranging from high-tech to multi-unit retail and distribution.  Her experience includes leadership positions with Microsoft, AT&T Wireless, Starbucks, and Vulcan Inc., where she managed Systems and Physical Security, Facilities and Operations, European Properties, Yachts, and Human Resources.  She helps organizations identify their vision, develop clear goals to achieve defined objectives, and establish systems that foster open communication and the exchange of ideas.  She is trained in mediation, detecting deception, and corporate investigations.  For Ms. Wolf’s full bio, please click here.


Tara Conway, MA

Threat Management Consultant

Expert Tara ConwayTara Conway is a Threat Management Consultant with SIGMA.  She has experience collaborating with national and international intelligence agencies Department of Defense elements, as well as local, state, and federal law enforcement agencies to analyze threats and coordinate efforts in the areas of response and prevention.  She is an accomplished briefer, having presented to well over 15,000 members of local, state, and federal law enforcement, private sector companies, and school personnel on matters of threat assessment and other intelligence topics.  For Ms. Conway’s full bio, please click here.




Emily Reineke, MA
Threat Management Consultant

Expert Emily ReinekeEmily Reineke is a Threat Management Consultant with SIGMA.  She previously worked for the Virginia Tech Police Department as the agency’s first Threat Assessment Team Coordinator, a position created to retain her expertise in threat assessment and program development.  She developed the team’s mission statement, created a database to manage all threat cases, designed the threat assessment team’s website an other educational materials for the campus community, and managed information flow for each weekly threat assessment team meeting.  She has collaborated with state agencies to plan and administer statewide trainining events for Virginia’s threat assessment teams.  For Ms. Reineke’s full bio, please click here.