What would GTA V be without its own spoof version of the FBI? The Federal Bureau of Investigation is either feared or looked down upon... depending on which rung of the ladder one is. They're meticulous, nosy and most everyday people think of them as meddling. The FIB in the GTA universe is the satirized version of the bureau. A corrupt and dangerous organisation, it also handles counter-terrorism and surveillance which is more the jurisdiction of the NSA. The FIB also maintains a rivalry with the IAA, just like the actual FBI often is at odds with the CIA.
The FIB has a rather prominent and flashy main building in downtown Los Santos, which actually has an interior. We point that out since it is something of a rarity in GTA V. The interior of the building is normally only accessible during the specific mission that takes place there, but this is GTA we're talking about. Players will find a glitch to get in anywhere sooner or later.
This glitch allows anyone to enter the FIB building in GTA Online and has been confirmed to work on the current-gen consoles and PC. The glitch requires the use of a Buzzard and a helpful buddy. You'll need to fly up to the skylight on the roof of the building and inch as close to it as you can with the pilot's door. Land, and get your helper to grab you out of the buzzard so that you'll fall onto the skylight.
Instead of having a nasty rendezvous with the skylight, your character will instead faceplant on the floor beneath, allowing you to freely explore the interior of the FIB building. Once you've had your fun, jump out of a wall breach or down the elevator shaft.
What other GTA V buildings have you glitched into?