FBI Agent is almost always pro-Town.
Use and Power
FBI Agent is one of the least-used power roles due to the infrequency of its success and its ability to shut down an entire faction if it is successful. Serial Killer is generally hard to win as to begin with, so unless the SK is very powerful, FBI Agent is not easy to rationalize in a setup.
As a result, games with FBI Agent are somewhat evenly split between those that have Serial Killers and those that don't. Unless there is evidence of an SK potentially being in the setup, FBI Agent is essentially a Named Townie.