You'd be amazed of the majority of ICE systems actually "owned" by DOJ. This comes from pre 9/11 when Immigration and Border Patrol were both part of DOJ. When they were brought under the DHS umbrella, those users remained on their respective systems and Customs (who were under Treasury at the time), remained on their legacy system after 9/11 as part of DHS. Yeah, one big dysfunctional family.
Many of the frequency assignments in the new Marshals system were integrated from the old INS/ICE vote scan system. In fact, many of the sites are still the same on both sides. In makes sense to consolidate, and this stance has been talked about since I believe 2004...google "DOJ integrated wireless network" and the concept has been discussed for almost 20 years now. Makes sense to share infrastructure and resources.
As far as the talkgroup names, that could have come from someone with access, but those codeplugs are CPS read locked. But those can also be obtained through FOIA requests...look at the Florida thread as an example of how it was easily done. But since they are strapped to encryption and they OTAR every month, you won't hear a thing. And I can tell you that 99% of the time, one of those agencies is on NJICS according to Unitrunker running on both systems. And if you look as sites alone between the two, it provides much better coverage. Oh and those are strapped ENC as well so again, you still won't hear a thing.
