Enemy Within

The Major Case Squad investigate the death of Harold Sternman, an elderly and paranoid banker who died in the penthouse suite of his own luxury apartment building during an arson fire. The investigation leads Goren and Eames to Harold's dysfunctional family, consisting of his young trophy wife Kit, his alcoholic son Edward, and Rick Zainer, Harold's private nurse. When DNA from Kit and Edward are found in Harold's bed, the detectives suspect Harold was using them as evidence to get divorced from Kit, but both Kit and Edward deny sleeping with each other; Edward is gay. Suspicion falls on Zainer, who admits to sleeping with Edward and turning the three family members against each other as revenge for Harold failing to deliver on a promise to write letters of recommendation for Zainer's sons to enter an elite private school. After increasing Harold's drug dose, which made him even more anxious and paranoid than usual, he led Harold to believe that Kit was cheating on him with his own son; Kit then conspired with Edward to kill him so she could get her inheritance and Edward would be left the apartment building, which he could promptly sell.