US Marshals Service

For several years now, the US Marshals Service, part of the Department of Justice, has been utilizing the FBI radio communications network for US Marshals operations. Initially, it seemed that the Marshals were just utilizing the same frequencies as the FBI operations. However, there now appears to be evidence that the US Marshals, or some other FBI units are starting to use some of the same frequencies, but are using a different P-25 Network Access Code (NAC).

Most FBI operational channels using P25 digital mode are using a NAC of N167. Some known FBI channels are now starting to show users with another NAC, in some cases N864. Since most of this traffic is encrypted, positive identification of the users is not possible, but reports from the New York City area have perhaps identified the N864 operations as "possibly" being US Marshals. This same NAC is being reported in other cites as well, and additional P-25 NACs have been seen on known FBI radio channels.

If these different NACs are exclusive to US Marshals units or perhaps a joint USMS/FBI task force is also unknown. In addition, there have been reports of some VHF simplex channels historically used by the US Marshals, such as 162.7875 MHz and 163.2000 MHz, being used with a NAC of N839.

So if you have the ability, keep an eye out for any unusual P-25 NACs on known DoJ channels in your area. We shall see if there is any pattern to the NACs used or any information on the users.