What episode of Bones is this?

So I like to watch the show Bones, with "Booth" and "Brennan" and so it is: A teen discovers a dismembered, headless body in a pool of purple of water; the team struggles to find enough evidence to locate a killer until getting insight from Zack,who studies the case at his psychiatric facility. So yea I just want to know the season and episode, please and thank you.