5 Things You Didn't Know About Criminal Minds, 'Tribute'

'Tribute'

'Tribute'

When former BAU team member and current Interpol agent Emily Prentiss tracked an international serial killer, she enlisted the help of her friends at the BAU after she was convinced the UnSub's next victim was on American soil.

Watch the full episode on CBS.com
A dose of fan mail.

A dose of fan mail.

Being a fan pays off! The name for Detective Inspector Louise Hulland was inspired by a Criminal Minds fan in the United Kingdom whom Writer Virgil Williams met through Twitter.
Something to write home about.

Something to write home about.

Why Chicago? Turns out that Criminal Minds writer Virgil Williams, who wrote "Tribute," is a Chicago native and set the episode in his old stomping grounds.
It's not just pizza that Chicago is famous for.

It's not just pizza that Chicago is famous for.

Which notorious criminals made Reid's map of Chicago? H.H. Holmes, William Heirens, Nathan Leopold Jr., Richard Loeb, Al Capone, Richard Speck, and John Wayne Gacy.
College grounds.

College grounds.

The episode's fictional "Northeast State University" is located in Evanston, IL., which also happens to be the location of the real prestigious Northwestern University.