We are available 24 hours a day 888-698-0077

Long Island Private Investigators

  • Home
  • Long Island Private Investigators

Long Island Private Investigators Over 10 Years of Trusted Expertise

Available 24/7 1-888-698-0077

What We Do

Long Island Private Investigators at Radius Investigations

Based on Long Island, Radius Investigations Inc. is located in Hauppauge, just minutes from the LIE, to be the most accessible resource for investigative services for the Long Island community.

Our licensed, insured, and bonded agency of private investigators are committed to providing quality and transparent private investigation and security services throughout Long Island, including Nassau County, Suffolk County, and New York City.

Our clientele are as diverse as the Long Island community, including: law firms, small-to-medium sized businesses, local and multi-national corporations, private clients, high-profile clients, financial professionals, religious institutions, and non-profits.

150 Motor Parkway Suite LL20
Hauppauge, NY 11788

Our expertise is unmatched.
Here are a few of our specialty private investigation services:

Why Choose Us?
Simple. We Are “No Bull”:

We are here to find answers, not take you for a ride.
We set ourselves apart from the rest with these simple rules:


From the moment we make contact, we provide top-quality services from bonded and licensed private investigators that deal in facts. We offer advice and solutions that will achieve the results you need for your case, not just sell you unnecessary fluff. Our final reports are comprehensive, thorough, and get straight to the point.


We don’t run and hide. We work with you every step of the way in getting intelligence. All of our clients have access to our online portal where you can view any recent updates to your case, as well as any video or photo documentation. We are available 24/7 to assist you and answer questions to your case.


As a veteran owned agency, we take on the military philosophy of never giving up and working as a team. We will work tirelessly and access our vast amount of resources and networks to give you the information you need to make informed decisions on your situation.


From our national and local charity work to you, our compassion towards your search for answers will never leave you feeling like nothing more than a number or case file. When you speak with us, we listen intently to understand your situation and give the best advice and strategies for your case, not just wait for you to stop talking so we can make our point.

What Our Clients Say About Us:

“Mr. Seifer provides a very professional, trustworthy service and is very knowledgeable in his field. He goes above and beyond to accommodate his clients to get the best results.”

-Lisa Martelloni

Product Management Engineering – Max Mobilcom

Our Lead Investigator

Meet Matthew Seifer: Expert Licensed Private Investigator, Registered Armed Guard, Technical Surveillance Countermeasure (TSCM) Specialist, and NYS DCJS Certified Instructor

Long Island Private Investigators 1

Matthew Seifer founded Radius Investigations in 2007. Seifer has an extensive background in private investigations and security, with over a decade of experience in these industries. Seifer is a U.S. Army veteran, with over 26 years in the private sector. He is not your typical PI: his work in security and education has made him evolve into not just a private investigator, but an instructor and mentor to help provide safety and security to the public. Matthew Seifer has been featured on local and national media platforms, including Inside Edition, for his work in providing active shooter response training and drills for schools and the workplace.

Mr. Seifer is described as strong and a born leader, as well as compassionate, dedicated, trustworthy, and diligent with his clients, students, and community. With his expertise and network of professionals, he can ensure that your needs will be answered anywhere in the world at anytime. He oversees every case and will follow through until the client has the answers they need to make an educated and informed decision.

Learn More about Matt Seifer’s Expertise, Work, and Community Involvement

Request a Free Estimate