Beginning in season one, establishing shots show the teams headquarters to be in a skyscraper which title cards identify as the "Boston Federal Building." However the building shown is actually Hancock Tower, a privately owned office building which is one of the most recognizable landmarks in Boston. The FBI is located in One Center Plaza which is across the street from Homeland Security office located in the John F. Kennedy Federal Building located downtown at Government Center. Both buildings are in direct proximity to Boston City Hall, a city courthouse, police station, local NBC/CW television station and immigration offices.
Whenever a shapeshifter is wounded they are shown to bleed "mercury." However, mercury is not sticky. It would not be stuck to the bodies or clothing around the wounds, nor stain the gloves of the investigators. It would simply spill onto the ground.