Castle Security Group

​​Private Investigations

About Us

For more information, email us a request at pbressler@castlesecuritygroup.net, or call (410) 788-7800.​

Call today for a free no-obligation quote!

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​​​Our goal is to provide accurate and timely information in a cost-effective manner that supports our clients in making decisions vital to their success.

 Castle Security Group is a Maryland private investigative agency.  Many of our private investigators are former police officers, police detectives or have military experience.

 Castle Security Group was established in 1981 by Frank Napfel.  We have served some of the largest corporations, law firms and insurance companies in the country.  We have taken a leading position in the movement to professionalize the investigative industry.  Castle maintains active memberships in the National Association of Legal Investigators, World Association of Detectives, and the Maryland Investigators and Security Association (MISA).

 Additionally, Frank has served four terms as president of MISA and on the Board of Directors of the Maryland Association of Contract Guard Agencies.  He has also served on the Governor's Executive Advisory Council and was chairman of a task force to study the impact of crime on business in Maryland.

 In August, 2016, Frank decided it was time spend a little more time fishing and less time in the office so he sold the agency to Paul Bressler, who has been with Castle for over 30 years.  Frank still offers his services as a consultant and for special projects.

MD State Police License No. 22PLU-SGPD3277