Question: what is the saddest episode of criminal minds?
Answer: Season 2, Episode 15: "Revelations" ... , Season 3, Episode 8: "Lucky" ... , Season 8, Episode 10: "The Lesson", Season 8, Episode 12: "Zugswang" ... , Season 5, Episode 16: "Mosely Lane" ... , Season 5, Episode 9: "100", Season 10, Episode 21: "Mr. ... , Season 5, Episode 12: "The Uncanny Valley"