Adding a bit to artbrooks-
Fort Hood Directorate of Emergency Services is a large group, headed by Mr. Charles Medley, civilian, offering police, and other services.

It is one of many Directorates at Fort Hood, listed on the Fort Hood website:
http://pao.hood.army.mil/directorates.aspx

Of these directorates, only the Hood Mobilization Brigade, and the Chaplains directorate, are headed by commissioned military officers. Most may be contacted by people outside the Fort, but not Emergency Services, Internal review, etc., which deal with security and policing.

Noted far above that Fort Hood essentially is a city; for the troops but with many civilian services. This is true of most military posts.