Capitol Offense

The NCIS team is investigating a murder, about which Gibbs is acting strange. It turns out that the murdered Lieutenant Commander was having an affair with Senator Patrick Kiley, a former Marine officer who served with Gibbs. Sen. Kiley tells Gibbs to suspect a lobbyist of the oil companies for the murder, but a remark from the Senator's wife leads Gibbs to deduce that they are the murderers, and they are both subsequently arrested. Meanwhile Abby is making an investigation of her own, trying to find out who stole her cupcake, a gift from Ziva, for her hospitality after the former's house is fumigated with McGee eventually being revealed as the cupcake thief.