To master Interrogation, you must master the skills of Business, Religion, and Science, by kidnapping and interrogating the CEO of a Corporation, a conservative Priest, and an Eminent Scientist, and using the default interrogation settings (no violence or food/water/sleep deprivation, no psychedelic drugs, keeping them strapped down so they can't escape, and trying to convert them). These interrogations will last a very, very long time, but you will be learning skills from them, skills that are used by Conservatives to avoid being converted during interrogation. If your stats are too low, you will be unable to get your skill level as high as whomever you are interrogating, so the interrogation could go on forever. Anyway, if your stats prevent you from getting your skill in Business, Religion, or Science as high as your hostage, eventually you will need to resort to psychedelic drugs and just keep using those drugs until you have them converted. The more interrogations you do, the higher your Interrogation skill gets, and violent/harsh interrogations build up your Interrogation skill faster than ones where you play nice. Never kill a hostage, even by accident: it will lower your Heart by a point, which is very bad. If you really want to get rid of a hostage, send them alone on a suicide mission after you have successfully brainwashed them, and have them pick a fight with someone much more powerful, and keep fighting on-site until they are dead. Never let a hostage or anyone else increase your Wisdom: to protect against this, back up the save.dat file regularly. If your Wisdom gets higher than your Heart, you are no longer loyal to the Liberal cause, and are likely to turn traitor if the police ever get you, or if you ever get into a fight with someone who uses a debate attack. Your Interrogation skill is capped by (Intelligence+Charisma)/2, and it is also good to have high Persuasion skill, which is capped by Charisma, when you interrogate people. And having high Heart and low Wisdom is also quite important for someone who does Interrogation (unless you actually want to kill the hostage for some strange reason, in which case you want someone with low Heart and high Wisdom to do the deed). If you made good choices at the
questions at the beginning, your founder should be the best person for doing interrogations. Intelligence, Charisma, and Persuasion are also quite useful in case the interrogator is ever arrested and put on trial and you choose to defend yourself, along with another skill: Law, which is best learned from Judges (Liberal Judge or Hangin' Judge, either one works). Of course, Law is not a skill you can learn through interrogation. You can only learn Interrogation, Business, Religion, and Science through interrogation. Once you become good at interrogation, you can easily make sleepers out of pretty much anyone in version 3.15.1. It was much harder in 3.12.2 (I didn't play any of the versions in between).