Brazil (S20E18)

When an environmental scientist, Dr. Oscar Silva (guest star Elliot Villar), is poisoned during a global warming symposium, Detectives Cyrus Lupo (Jeremy Sisto) and Kevin Bernard (Anthony Anderson) initially suspect competitors from Dr. Silva's field of study. It is soon discovered that Dr. Silva is involved in a messy custody battle with his wife's (guest star Tammy Blanchard) ex-husband, Phillip Shoemaker (guest star Tony Hale) and the focus of the investigation quickly shifts to the victim's family. Meanwhile, the case becomes personal for Cutter (Linus Roache) as it stirs up unpleasant memories from his own past. (iTunes)