DHS never could run investigations. They were filled, by Dubya, to be a purely preventive thing. Like discovering sleeper cells. They had a focus kind of like the FR Threat Matrix.
Of course, the rot started almost instantly, importing folks from ADL and tying knots with charlatan outfits like Symantec, who supplied some of their early leaders. Could just as well have hired al Quaida.
Thank you for clearing that up for me Hardraade, I couldn't even tell you their purpose.
I am sure the Muslim Brotherhood has made their presences known though. :\