Psychology, Psychiatry, Criminology? What's the difference?

I am aiming towards being an FBI Special Agent. I know i need 3 years professional work experience, and I know i need to enter through one of the five entry points. I'm entering through the Language entry point, but i also need to ask. If one day I decided to go for the Supervisory special agent job, I know that they do alot of thinking and have to know what the criminal was thinking or what theyre about to do next. Which one do they use, Psychology, Psychiatry, Criminology, or are there other forms? And i also know that there are certain types of the 3 above for example forensic psychology, forensic psychiatry, etc. I'd like to know exactly what they use in the work field?