EXPERIENCE AND VISION
EXPERIENCE AND VISION
Guardian Security Investigation & Training, previously named Guardian Investigations, centrally located on Long Island in Hauppauge, NY, was formed in 2007 by Matthew Seifer, a Licensed Private Investigator, Registered Armed Guard, and Division of Criminal Justice Services (DCJS) Certified Instructor.
We have established ourselves as a leading force in surveillance, insurance investigations, and security services; coupled with expertise in corporate due diligence and background investigations, security consultation, litigation support, fraud, and internal investigations. Our firm has an experienced and diverse team of investigators, ranging from retired law enforcement, legal practice, and military service, available in New York, nationwide, and around the world.
You can expect nothing less than sensitivity, confidentiality, thoroughness, expertise, professionalism, and integrity in services from Guardian Investigations. We take great care and pride in our cases; We do everything possible to reach a resolution to your case.
Guardian Investigations helps law firms, companies, religious institutions, and individuals solve problems, advance business opportunities, mitigate risk, win or avoid lawsuits, and resolve disputes.

PROTECTION THROUGH EDUCATION & TRAINING
Guardian Security Training provides New York State approved security guard training courses for Long Island and NYC. GST is the only training facility on Long Island to offer not only security guard courses, but private investigator development, HR218, conceal carry courses, and active shooter response seminars and drills.
OUR MISSION IS SIMPLE: TO PROVIDE HIGH QUALITY EDUCATION TO BUILD UP QUALIFIED CANDIDATES, RESULTING IN QUALITY PROTECTORS FOR OUR COMMUNITY.
Our Clients
Meet the Team
Our quality professional instructors come from a range of backgrounds: Private Investigations,Law Enforcement, Federal Agents, and Military.

Dwight Hovington
DCJS Certified General Topics Security Guard Instructor,
Licensed Private Investigator,
Crisis Prevention Intervention,
Active Shooter Training
Dwight Hovington is a retired and highly decorated New York City Police Detective Investigator. He was responsible for investigating complex cases of organized crime which resulted in the arrests and prosecution of individuals charged with federal, state, and local crimes.
Mr. Hovington received his specialized training from the NYPD and the United States Secret Service in Dignitary Protection and fraud investigations. Through his robust background, he has extensive years of experience in civil, matrimonial, insurance, and corporate investigations. His previous experience also includes having the responsibility of the protection of numerous dignitaries and celebrities abroad. As a licensed private investigator, Hovington specializes in surveillance, background and due diligence investigations, infidelity cases, executive protection, and threat assessments.
Hovington’s expertise covers the general topics in the security guard training curriculum, as well as the Introduction to Private Investigations course.

Don Lettieri
NYS DCJS Certified General Topics and Armed Security Guard Instructor,
Utah Conceal Carry Instructor,
NRA Firearms Instructor & Training Counselor,
NYS Registered Armed Guard,
USAF Veteran,
Retired Federal Officer
Don Lettieri is a US Veteran and retired Federal Officer from the US Department of Justice and the Federal Bureau of Prisons. In his 23 years of service, Lettieri provided firearms and less-than-lethal munitions training for the Justice Department. With Mr. Lettieri’s decades of experience in firearms instruction, he has received his professional instructor certifications from agencies including the NRA, NYS Division of Criminal Justice Services, and Utah Department of Public Safety.
Mr. Lettieri’s instructional methodology is to always provide instruction that follows the student’s pace. He has trained from the most novice to the most seasoned officers in the safe and proper handling of firearms.
Lettieri is the top professional in providing instruction for general security guard topics, armed security guard courses, firearms training, and Utah conceal carry weapons courses.

Jason Green
NYS DCJS Certified General Topics and Armed Security Guard Instructor,
LEOSA HR218 Instructor,
Instructor in Defensive Tactics,
ASP Tactical Weapons,
Handcuffing Aerosol Subject Restraint,
Texas A&M CRASE,
Glock Advanced Armorer
Jason Green has an exhaustive list of experience and accolades too long to list in a quick biography. A summary of his work includes over two decades of firefighting and Emergency Medical Technician (EMT) experience. Mr. Green has several instructor certifications, including fire service, NYS DCJS Instructor certifications in general topics, as well as law enforcement training and active shooter response training.
As a member of the Law Enforcement Trainers and Educators Association, Mr. Green emphasizes quality education for those who serve in law enforcement, as well as the general public in matters of proper safety and security procedures.
Green’s specializes in providing instruction for armed security training, LEOSA HR218, Handcuffing and Aerosol Restraint training, and unarmed security guard courses.