For several weeks, Claire had the feeling that she was being stalked, and her suspicions were proven correct when she was confronted by a psychotic woman named Jessica Fenton, who introduced herself as Dwight's mistress. Jessica revealed their affair to Claire, who responded by bludgeoning Jessica with a fireplace poker. After her taunting continued, Claire tied Jessica to a chair and relentlessly beat her with the poker, resulting in Jessica's death in spite of Dwight's attempt to get between the two.
During the murder, Claire accidentally struck her husband with the weapon, but after Ethan entered the room and Heather returned home, Claire lashed out a bit at Dwight in response to her children's questions regarding Jessica and the crime that had just been perpetrated. It was there that Dwight and the rest of the family decided to cover up Jessica's murder, first by burying her body at Red Rock Canyon, and then by inviting Doug Adamson—a recovering addict—to stay at the home. Adamson's stay was to set him up as a murderer, with the family as his victims.
After Dwight was found dead and upon learning that he was killed by Ethan (due to finding out about his father sleeping with Jessica, as well as Ethan being a pawn in her vengeful plot), the CSIs searched for Claire, Ethan, and Heather. Only Heather was found, and the end of the episode revealed that both Claire and Ethan were murdered, with the assumption that both murders were committed by Heather.