Books are shelved in general subject categories using the Library of Congress classification system. You may want to supplement your use of the catalog with browsing shelf areas for your topic.
Books relevant to forensic psychology are shelved in various call number areas, including:
To limit your search to movies, look for the notation, "Gustavus Library Audio Visual." DVDs are shelved on the library's lower level by the call number (call number PN1997 .O543 1997, in the example below).
https://www.imdb.com/ is a database of movies that contains a number of movies and TV shows tagged with the phrase "forensic psychology."
I consulted some film bibliographies and created a list of movies and TV with forensic psychologists in their synopses.
Librarians are here to help!