FYI:

FBI Tactical Aviation Pilot Job Description

Within the Tactical Aviation Unit is the Tactical Helicopter Unit (THU), which is tasked to the HRT. The THU flies a fleet of tactical transport helicopters including at least 8 UH-60 Black Hawks, as well as some McDonnell Douglas 530 Little Bird light helicopters. The helicopter pilots assigned to the HRT groups are responsible for maintaining optimal mission performance, which requires daily training flights.

[link to www.fbiagentedu.org (secure)]

So, the blackhawks are assigned to the HRT. I imagine they can be tasked for other purposes, but something emergent happened to warrant a helicopter, as opposed to a ground vehicle excursion.

I wonder where the closest FBI office with a blackhawk is located?