Our Team

John G. Yunk, III


John G. Yunk III is a retired Captain of the Pennsylvania State Police (PSP), honorably discharged after having served 27 years with the agency. He currently holds the position as Director of Operations and Professional Training with Valentis Group, Inc. He oversees daily operations of the company, with clients based in various states, and coordinates the training advancement of all Valentis personnel. In his previous career, John commanded the third busiest PSP station in the Commonwealth and served as the Operations Commander for the Domestic Security Section Division. Part of his duties included preparing and equipping the Pennsylvania State Police and Commonwealth partners to prevent and mitigate event impacts through support planning, training, and resourcing.

As he progressed through the ranks, he served patrol, criminal investigation, and staff services functions in the Harrisburg region: The Bureau of Drug Law Enforcement, The Bureau of Criminal Investigation, The Bureau of Forensic Services, and the Bureau of Emergency and Special Operations where he served as Commander for the agency’s Special Emergency Response Team; Canine Section; Hazardous Device and Explosives Section; Aviation Section; Equestrian Section and Electronic Surveillance Section.

John was the 8-year lead for the PSP Incident Management Team (PSP-IMT) and served during the Frein manhunt, the Baltimore City Support Detail, the 2016 Democratic National Convention, the Papal Visit, and the Pennsylvania Governors Inauguration. He received several significant service awards from the Department, including a Commissioner’s Commendation. He is certified in many disciplines and was the lead instructor for four years for Active Shooter training, having presented to tens of thousands of individuals in both the public and private sectors. Presentations have also been provided to local, county, and state agencies, school districts, businesses, and a variety of other venues.

John is a graduate, with magna cum laude honors, from the University of Pittsburgh. He is also a graduate of the Northwestern University, Center for Public Safety, School of Police Staff and Command, notably with summa cum laude honors.
John is the Director and one of our instructors at ASLET.

Justin Havens is a distinguished veteran of the United States Air Force, having served six years. During his service commitment, he and his military unit provided support and assistance in the recovery efforts after the 2011 Tōhoku earthquake and tsunami hit Japan in 2011. Additionally, Justin was deployed to an undisclosed area of the Middle East during Operation Enduring Freedom, a name synonymously used by the United States government for both the War in Afghanistan (2001–2014) and the larger-scale Global War on Terrorism, in which he provided critical supply of equipment in response to the war efforts.

Justin has a significant background in firearms and associated training, whereas he obtained an Expert Marksman badge from the United States Air Force.  He is certified with several National organizations, which include the National Rifle Association and the United States Concealed Carry Association. Before instructing for ASLET, Mr. Havens operated his own civilian training company.  The company has instructed well over two hundred students on firearm responsibility and safe firearms ownership.  Justin is certified as an instructor for Active Shooter and associated threats, Oleoresin Capsicum (Pepper) spray training and deployment, and is one of the first fifty recognized certified instructors in the Ultimate Training Munitions Civilian Program instructors in the country.

In addition to being the lead instructor at ASLET, Justin is the Technical Training Commander for Valentis Group, Inc.  To maintain the highest training standards in the contract security industry, Justin brings a clear vision and direction to Valentis, which expands upon their belief in the need for advanced critical training for their staff across the Nation.  Justin holds train-the-trainer certification with Valentis Group, Inc. in Academics and Use of Force, Firearms, and Defensive Tactics.  During his tenure, Justin has revamped areas of training that now exceed expectations in training staff to recognize, prevent, and combat against all threats, large or small.   

Justin Havens

Lead Instructor

Michael Gressem


Michael has been involved in contract private security since 2007. Before launching a career in security, he served as a school police officer. Michael is a certified skills instructor for the Pennsylvania Act 235 program. He is also certified to teach several disciplines, including threat patterns and use of force, edge weapons, and countermeasures, Lamperd less lethal door breaching, munitions, and crowd control.

Micheal serves in a full time role as Regional Commander with Valentis Group, Inc, and oversees multiple state operation that provides armed security services to commercial and government clients. Additionally, Michael is a certified company trainer with Valentis and serves as a lead facilitator on the company’s force-on-force, scenario-based qualification program.  

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