About ComSec LLC

TSCM, Cyber TSCM, Technical Surveillance Countermeasures & Counter Surveillance Experts. ComSec LLC is a leading TSCM Services, Cyber TSCM Services & TSCM Equipment Solutions provider. Serving business, government, military, law enforcement, and executives USA nationwide & globally. We utilize proprietary processes, skilled Specialists, and the most advanced TSCM equipment available to detect, locate and neutralize technical surveillance threats and vulnerabilities. ComSec LLC also develops and supplies TSCM equipment to government, military, law enforcement, TSCM practitioners and corporate clients.

Our Products

Non Linear Junction Detector

Non Linear Junction Detector EDD-24T. Powerful, Sensitive, Compact, Handheld & Lightweight NLJD for Professional TSCM Applications.

Kestrel TSCM Professional Software

Kestrel TSCM Professional Software is an industry leading, award winning RF spectral analysis software for TSCM professionals.
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Technical Surveillance Countermeasures - Points in Your Organization


The scope of a server's duties can differ extensively, with having to serve clients in different buildings or even different cities, while Local Area Network servers usually only cover a room or office. However, both WAN and LAN servers use the same fundamental processes when getting data to their clients.


Hardware firewalls are special machines that are switched between the internal network of a company or an Internet provider and the Internet. They are designed to prevent hacker attacks, denial-of-service attacks and spam - and at the same time let the company's employees who log into the corporate network via a VPN connection (Virtual Private Network).


Routers are special computers that help to network the internal network of a company or an Internet provider, but also forward and process Internet traffic.


Firewalls can be either hardware or software but the ideal configuration will consist of both. In addition to limiting access to your computer and network, a firewall is also useful for allowing remote access to a private network through secure authentication certificates and logins.

Room Surveillance

Many "spy shop" devices are generally low-cost consumer electronic devices that have been modified for covert surveillance. They are easy to use against unsuspecting targets. Devices produced for industrial espionage are more expensive, more sophisticated, and more difficult to find during a technical surveillance countermeasures (TSCM) inspection. Devices designed and built for intelligence services are still more expensive and very difficult to find.

Wireless LAN

Wireless LAN or WLAN refers to Wireless Local Access Network. A wireless network is a network that uses radio waves to link computers and other devices together. Wireless networks are accessible to anyone within the router’s transmission radius. This makes them vulnerable to attacks.


Computers are similar to telephones, in that they have the essential parts for a sophisticated surveillance system, a microphone and a means of communicating information outside the area in which they are located. Computers are vulnerable to several types of eavesdropping operations.


One method of technical surveillance attack over USB is masked as the average flash drive. Deploying a keystroke injection attack is both easy and effective. The "USB Rubber Ducky" flash drive is recognized on computers as a generic keyboard. With this identification, the USB flash drive can perform keystroke injection attacks.


A bug in your keyboard, or "keystroke logger" could transmit every keystroke so that everything you write can be reproduced...

Computer Monitor Surveillance

Standard computer screens emit faint electromagnetic radiation that a very sophisticated eavesdropper can use to reconstruct the contents of the computer screen. These signals can carry a distance of several hundred feet, and even further if exposed cables or telephone lines act as inadvertent antennas. Security measures and shielding are available to reduce the risk of such eavesdropping.

Mobile Phones

ComSec’s cell phone forensics service provides data extraction and detects cell phone spyware. And, our cell phone forensics service also includes a comprehensive email report of cell phone contents (active and deleted.) ComSe’c cell phone forensics service is a professional level service. Specifically, we use Cellebrite cell phone forensics technology, which is preferred by law enforcement, military and intelligence services.
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Cell Phone Networks

An adversary could set up a rogue cellular base station and then use it to eavesdrop on or manipulate cellular device communication. IMSI-catchers or cell-site simulators work by pretending to be a legitimate cell tower that a smartphone would typically use. The catchers trick the cell phone into sending identifying information about its location and how it is communicating. ComSec recognizes the acute nature and escalating frequency of cellular surveillance attacks. In response, we developed the capability to detect rogue cellular base station surveillance and provide actionable real-time information to our business clientele.
ComSec's Team are "Best-in-Class" and will deliver top-quality performance & customer-service...In my opinion, especially when it come to counter-espionage services you can lean-on & trust, ComSec has no peers.


Joseph S., President, Corporate Client
I can’t tell you how thankful I am to have done business with you. Your services are worth every penny. The peace of mind is immeasurable!

Hired ComSec for Residential TSCM/Cyber TSCM Services in 2021

PAUL J., AZ, Residential Client
It was a pleasure to meet and work with Frank also. We'll definitely use ComSec again should we need additional services.
I appreciate your help with everything!

Hired ComSec for Corporate TSCM/Cyber TSCM Services in 2020

Pam, CA, Corporate Client
Thank you all again for your assistance in this matter. It has been a pleasure working with Frank, John G. and you.

Hired ComSec for Corporate TSCM/Cyber TSCM Services in 2020

Paul, FL, Corporate Client
This company is the real deal. I had a situation where it was questionable if I was being bugged. I was referred to JD and his company. In speaking with JD over the phone for the initial discussion he was clear, direct, and professional. The end result was my concerns were alleviated and I could not be happier. I highly recommend him and his company.

Contacted ComSec LLC in 2020

MS, Weymouth, MA
We're so glad we hired ComSec. Thanks for hunting down the issue and helping correct the problems. Excellent service and team!

Hired ComSec for Corporate TSCM/Cyber TSCM Services in 2020

Steve, OH, Corporate Client
Thank so much for the help! The peace of mind is so valuable.

Hired ComSec for Residential TSCM/Cyber TSCM Services in 2020

Mark, CO, Home Owner
Everyone we dealt with at ComSec was knowledge and helpful. We definitely hired the right company. Thanks so much!

Hired ComSec for Corporate TSCM/Cyber TSCM Services in 2020

A.Z., NYC, Corporate Client
J.D., your technical expertise and equipment are very impressive. Thanks for level of service provided. I'm very confident in your services and appreciate the attention I was given and all of the help.

Hired ComSec for Residential TSCM/Cyber TSCM Services in 2019

Adrien, CA, Tech Executive
Your team was responsive to our needs on such short notice. We will definitely recommend ComSec to colleagues in need.

Hired ComSec for Pre-Meeting TSCM/Cyber TSCM Services in 2019

Paul, Washington DC, Government Contractor
J.D.'s expertise and knowledge set him apart in the industry. We would not trust anyone else with performing TSCM/Cyber TSCM services of our aircraft!

Hired ComSec for Aircraft TSCM/Cyber TSCM Services in 2019

Howard, TX, Corporate Client
You did such a great job the last time, I'll be using your services for all of my clients.

Hired ComSec for Cellphone Forensics Services in 2019

Dave, TX, Corporate Client
ComSec has been performing pre-meeting sweep services and in-conference monitoring for our corporate events for several years. We could not be more pleased with J.D.'s expertise, the level of services provided and the overall responsiveness of the ComSec team. Great Job!

Hired ComSec for Meeting TSCM/Cyber TSCM in 2019

Paula, MD, Corporate Client
The level of service and the technical knowledge of your team far exceeded our expectations. We will definitely be contacting ComSec for services in the future.

Hired ComSec for TSCM/Cyber TSCM in 2019

Ted, NYC, Corporate Client
I am deeply thankful for the peace of mind your service has provided me with.

Hired ComSec for TSCM / Cyber TSCM Services in 2018

Paula, WA, Residential Client
Thanks a million to you and Lisa for taking on this job on such short notice. Trust me, you have secured a spot on our very short list of companies to call when we find ourselves in need of such services. Thanks again for the swift response to our very urgent call for assistance.

Hired ComSec for TSCM/Cyber TSCM Services in 2018.

Corporate Client, Fortune 500 Company
Thank you very much for the quick turnaround. Frank did a great job and was very professional. We appreciate your help in giving us peace of mind with our concerns. The whole process working with you all was very efficient, professional and organized. We will definitely call you in the future if we need additional services. Thanks again!

Hired ComSec for TSCM / Cyber TSCM Services in 2017

Corporate Client, PW, Baltimore, MD, TSCM/CYBER TSCM Services 2017
J.D. & Brent were great to work with! We will definitely use your services again.

Hired ComSec for TSCM / Cyber TSCM Services in 2017

Corporate Client, A.R., District of Columbia, TSCM/CYBER TSCM Services 2017
I was very satisfied with the service provided, your availability, your responsiveness and the overall experience. I will definitely recommend your company to friends and colleagues.

Hired ComSec for TSCM / Cyber TSCM Services in 2017

KH, Maryland, TSCM/CYBER TSCM Services 2017
Very much appreciate your help in moving this logistically so quickly! We will definitely recommend you all to our friends and partners.

Hired ComSec for Cyber TSCM Services in 2017

Corporate Client, Michael, Washington, DC, TSCM/CYBER TSCM Services 2017
What an amazing company and individual who really cares and wants to help his customers i thank you JD!

Hired ComSec for Cyber TSCM Services in 2016 & 2017

Corporate Client, Los Angeles, CA – Cyber TSCM Services 2016 & 2017
Thanks for sending the reports through JD. We appreciate the expert tscm services you and your team provided. V/r, SJ

Hired ComSec for multiple TSCM / Cyber Services in 2016

Corporate Client – SJ, Washington, DC – 2016
Good morning J.D., I have successfully retrieved the report and downloaded the contents of the folder. I want you to know that you have put my mind at easy and given me the freedom to carry on with my daily activities minus the worry, stress, and fear. I greatly appreciate your integrity! Good luck on all of your future endeavors! Warmest Regards, R.A.
RA – TX-2016
I came across J.D. when I was managing a large-scale cyber incident response for a F500 company, who had had their computer networks breached by Chinese nationals. The investigation led us throughout the world, with on-site inspections in Beijing, Shanghai, Singapore, Mumbai, Mangalore and several locations in the United States. J.D. proved himself a consummate professional during that response, doing what he said, when he said he would do it, on or before deadline, at cost, as promised. I have subsequently engaged J.D. in a personal protection detail to clean a residence of a high-profile individual who was the subject of death threats and who was feeling vulnerable. J.D.’s work ensured the person was assured of their privacy and attained a peace of mind they had not felt in some time. Again, as promised, on time, on budget. I recommend J.D. wholeheartedly and without reservation for TSCM work.
NS, TX – 2016
J.D. Leasure’s performance in the field of TSCM/Cyber TSCM is outstanding in every respect. I’ve interacted with and worked around J.D. Leasure for a number of years, during that time I’ve know his work to be of the highest quality and integrity. His experience in the field of Technical Countermeasures is extensive (i.e., just read his BIO) and consistently exceeds the expectations of the clients I have forwarded to him. J.D. is smart, methodical in his approach and he runs a lean company so if you are interested in protecting your intellectual property or have a need for his services give Mr. Leasure and his team at ComSec a call.
MG, VA – 2016
J. D., I just wanted you to know that I truly trust your expertise and feel honored that you took my assignment. Your professionalism and ability to get to the bottom of the situation quickly exceeded my expectations. Your thorough sweep and suggestions were a vital part of my peace, and for that, I am most grateful. Thanks again
Best regards, JC

Hired Comsec in 2016

Really enjoyed meeting the team and I think everything worked out great for my company’s needs.

Hired ComSec for TSCM / Cyber Services in 2016

J.D. and Johnny are Awesome! They are both knowledgeable, professional and a pleasure to work with! Thank you and Johnny for all of your hard work! It was definitely a pleasure!

Hired ComSec for multiple Cyber TSCM Services in 2015 & 2016

ARS – San Antonio,TX
ComSec is responsive, thorough, and knowledgeable.

Hired ComSec for Cyber TSCM Services in 2015

PM in DC
You and your team did a fantastic job JD! Keep up the good work!

Hired ComSec for Cyber TSCM Services in 2015

M.D.S., Michigan (Corporate Client).

Hired ComSec for Cyber TSCM Services in 2015

M.K.L., New York, NY (Fortune 500 Client).
I feel that the service that was provided was excellent. When dealing with a situation that includes potential privacy breech, you need someone that firstly, knows what they are doing and secondly that listens and responds to each concern. I feel that both objectives were met with ComSec. Thank you for the help.

Hired ComSec for Cyber TSCM Services in 2015

“Heather”, Residential Client
The response and attitude of your team was outstanding. Will definitely use ComSec again!

Hired ComSec for Cyber TSCM Services in 2014

“William”, Fortune 500 Corporation
Working with JD was a great experience. He was very knowledgeable, courteous and timely. A++!

Hired ComSec for Cyber TSCM Services in 2014

“Barret”, Fortune 500 Corporation
J.D. is of highest moral aptitude, character and intelligence that I have had the pleasure to work with for some time. I hold J.D.’s opinions at the highest esteem and respect. From the vast knowledge that he possesses, I consider Mr.LeaSure’s counterespionage expertise an asset in any business, diplomatic, intelligence or security venture on the global scale invaluable.

Government of Israel

Jacob Goldberg
J.D.’s team responded to a highly critical situation within hours of the first contact. Upon arrival at the site – the project initiated immediately and resulted in an extremely satisfied client that subsequently requested J.D.’s team on followup engagements.

Hired ComSec for Cyber TSCM Services in 2010, 2011, 2012, 2013, 2014,2015

Jarrett Kolthoff, President/CEO SpearTip, LLC
Mr. LeaSure's extraordinary field experience for the past several decades helps to ensure both an accurate and successful meeting. His vast knowledge and equipment makes him the best in his field. I am so excited to describe my experience with ComSec and assure all of you what great success I had hiring him. The best decision I have made. Don’t leave any doubt if, you have suspicions BRAVO

President of Osprey Spill Control (OSC)

Mary Meyer
I first spoke with J.D. after discovering what appeared to be a battery operated electronic listening device hidden in my office. J.D. counseled me on the precautionary steps that I should immediately take while he worked to identify the device. Within an hour of emailing a photo to J.D., he responded with an exact identification of the device, including source information and additional go-forward advice.This instance turned out to be a harmless office prank that did not involve an actual listening device. The person responsible was identified and completely disclosed their intentions. It is reassuring to know that had this been a real threat to the security of confidential information, J.D. was there to identify and remove the threat. If you are looking for a true professional who takes your concerns seriously, I highly recommend contacting J.D. I surely will.

Baxter Healthcare Corporation

Perry Crumbaker
Director of Business Operations
Spillane Associates has had the pleasure of using the technical services of J.D. in the field of TSCM (Technical Surveillance Counter Measures) for our high-profile client. Aside from the extremely high quality of work that was provided, J.D. worked around a challenging client schedule to accomplish the TSCM. Above all, J.D. made the client comfortable and secure while maintaining the level of service expected from Spillane Associates. I would not hesitate to use the proven services of J.D. LeaSure for any of our clients in the future.

Investigator at NJ Department of Banking & Insurance

Robert Spillane
There is no other way to describe J.D., other than he is the quintessential consummate professional. I use his firm frequently for my high profile clients

Hired ComSec for Cyber TSCM Services in 2010, 2011, 2012, 2013, 2014,2015

Owner, Samuel Yount Investigations, Inc.
I have personally and professionally known JD for well over 20 years. JD has always presented himself in the most professional manner. Serving in Special Forces and requiring equipment of the highest standard has always been our benchmark of operation and settle for nothing less. JD consistently provided our unit with the highest grade, cutting edge technology products on the market. I strongly recommend anyone looking for the highest professional TSCM service, from some one who truly has the client’s best interest at hand. Understanding the needs of our current security corporate culture climate, where confidentially, timeliness, and accuracy is a must, anyone looking for these specific capabilities should speak with JD about his line of cutting edge TSCM services that are truly second to none. Brent Delorier CWO (R) US Army, Special Forces

  • Brent Delorier, CWO (R), US Army, Special Forces
  • Brent Delorier, Associate
  • Booz Allen Hamilton, Virginia
  • Testimonial, US Army, Special Forces

President/CEO at Jäger Group LLC

Brent Delorier
I have known J.D. for a number of years now. J.D’s expertise in the areas of TSCM, Counterespionage and espionage detection methods is, by far, the most detailed and professional that I have seen in the industry. His skills and professional services come with my highest recommendation!

Hired ComSec for Cyber TSCM Services in 2010, 2011, 2012, 2013, 2014

Kristopher Bleich, EnCE, C|EH
Director of Forensic Services, SpearTip LLC
J.D., so sorry for my late response. I did receive your report and have taken your recommendations to my IT manager for further action. Thank you for your professional service and your quick availability. Your work has allowed many of us to rest easier. Thank you for everything.
Top qualities: Expert, On Time, High Integrity

Hired ComSec for Cyber TSCM Services in 2013

“Jenny” PA, USA
Thank you, J.D. I now know who to go to for future needs and who to recommend to my associates – yes, it’s you!
Top qualities: Great Results, Expert, High Integrity

Hired ComSec for Cyber TSCM Services in 2013, 2014

“Robert” Washington, DC
JD, Thanks for the detailed report, and for the thorough service. I would use your service again, and would certainly recommend you to others.

Hired ComSec for Cyber TSCM Services in 2013, 2014

“Todd” Knoxville, KY USA
J.D. Your team did an excellent job at our facility. Truly an exceptional team and service! V/r

Hired ComSec for Cyber TSCM Services in 2014

“J.R.” D.C., USA
Great team of experts who are proficient and knowledgeable in this business. It was a pleasure working with ComSec LLC!

Hired ComSec for Cyber TSCM Services in 2014

“S.S.” MD, USA
We are very satisfied, and happy with the personalized service and availability of ComSec to suit our customized needs.

Hired ComSec for Cyber TSCM Services in 2014

“Fortune 100 Corporation”
Your organization is one of the most professional and knowledgeable in the industry, that we have had the pleasure to work with...

Hired ComSec for Cyber TSCM Services in 2011, 2012, 2013, 2014

“John” U.S. Defense Contractor
The response and attitude of your team was outstanding. Will definitely use ComSec again.

Hired ComSec for Cyber TSCM Services in 2013 & October 2014

“Bill”, Fortune 500 Corporation
Thank you! I appreciate how fast you were able to get here and help me!

Hired ComSec for Cyber TSCM Services in 2014

“Carrie”, Small Business owner