I have not finished the game yet, but I must have missed something because I don't understand the FIB's motivation for getting Michael and the gang to mess with the IAA. the first mission you have with Dave he talks about an informant that will expose the corruption within the FIB so you go in to the morgue to check if he is actually dead or not.Then you kidnap the guy and torture him, I have no idea why you kidnap him, how he has information on the FIB or why you have to kill the guy he gives up during the interrogation. Now I am getting towards the end of the game and the FIB guys keep talking about funding that they need and now I have to steal nerve gas but I have no idea why and it's really confusing me.
Sorry if I am coming across as stupid, I just feel like I have missed some vital piece of information that will make it all make sense, or I am just not at the point in the game where it has been revealed yet.
Any help understanding would be appreciated.