CBS

Season 8: Episode 11 - Who's There?

Who's There?: ­When two armed intruders take hostage of a rich couple named Elizabeth and Ron Ferguson in their home, Ron is killed and Elizabeth wounded. At the crime scene, the CSI team find a fragment of a playing card on Ron’s corpse and an empty, unlabeled package box in the room. When Elizabeth heard a knock on the door, she saw the package and opened the door, allowing the intruders to enter. They stole the contents of the Ferguson’s safe and bound them, but Ron was able to tackle one of the intruders and take off his mask, allowing Elizabeth to see the criminal’s face. Their daughter, Megan, has an alibi—she was at the movies and has a ticket stub to prove it. Back at the lab, Lindsay finds remains of scented candles in the box, which she uses to track down customers from candle manufacturers, leading her to Mark Johnston, who matches the composite sketch perfectly. Mark explains that things got out of hand, but declares his innocence. Phillip Roth, Ron’s business partner, becomes a suspect when angry voicemails are found, and Roth reveals that Ron was ruining their business to stop Elizabeth from attaining any of his assets in the case of divorce. Adam discovers that the card comes from the same movie theater as Megan’s alibi and the truth is unraveled: Mark is Megan’s boyfriend and they robbed her parents so to run away together; Megan could not stand to live with the animosity of her parents. Elizabeth took advantage of the invasion and smothered her husband to death to avoid a messy divorce.