[WATCH] 'NCIS: Los Angeles' Sneak Peek: Deeks Makes a Gruesome Discovery

The case in NCIS: Los Angeles season 9 episode 17 looks like something right out of Criminal Minds. In "The Monster," the team's investigation into a missing person uncovers a killer who puts on shows for high-paying voyeurs.

This episode is likely also going to reveal more about Mosley, as the assistant director assigns Callen as her partner on a joint ATF mission to apprehend someone from her past.