Each state is different when it comes to how they operate their police academies. In many states, there is a regional board of administrators who decide how the local police academy will operate. They are in charge of setting the standards for admission for potential cadets and other qualified applicants. In addition to those basic criteria, they also handle the curriculum that will be taught at the academy. This is important for two reasons. First of all, it is vital to have a basic fundamental knowledge of police work for all cadets, officers, and police men and women. Secondly, state run academies generally administer a standardized test needed for graduation that ensures competency across all forms of police work. These subjects include legal matters, crime scene protocol, and other basic tenets of being an officer.
At a more local level, the state schools may be in charge of their own hiring practices, including current standing law enforcement officials brought in to teach particular subjects relevant to a cadet's training. At higher level positions however, the state regulatory board is likely in charge of hiring and firing the top levels of educators and administrators in the police academy network. There are many variations in these practices between each state, so your best bet is to contact local officials and determine the standards in your area.
Police Academy