When 18-year-old Brian Partney is murdered in a hotel elevator while on vacation with his parents, Horatio suspects Brian was randomly killed as a gang initiation, because a black bandana was left at the crime scene. [Edit]

When 18-year-old Brian Partney is murdered in a hotel elevator while on vacation with his parents, Horatio suspects Brian was randomly killed as a gang initiation, because a black bandana was left at the crime scene. A key card on the victim leads to Mitch Pena, a guest who happens to be staying on the same floor on which the elevator stopped when Brian was shot. Pena insists that he scared Brian when he got too close to Pena's girlfriend, but he had no reason to murder him. Shane, Brian's younger brother, recalls seeing a guy speed away on a motorcycle at the time of the murder. Tread marks and vegetable oil used for performance bikes lead the CSIs to a bike shop owned by Vasco Torres, who has known connections to the Cobra gang. Unfortunately, when the team gets to the bike yard, the bike Shane spotted is on fire, leaving the team with nothing. They also question Luis Mendoza, the hotel bellman who handled the Partneys' luggage. Mendoza lives in gang territory, and his uniform jacket was found with Brian's blood, but he swears he's innocent. When Brian's father, Roger, vows revenge, threatening to take matters into his own hands, Horatio has him followed. However, Horatio is unable to prevent Mendoza from being attacked while working his second job at a construction site. The CSIs eventually learn that Shane, angry about his brother's murder, attacked Mendoza. Still on the hunt for Brian's murderer, Calleigh and Delko track down a pocket watch that Brian carried and find the missing bullet at the bottom of the elevator shaft. In the end, the CSIs piece together what really happened: Mitch Pena gave Vasco Torres his gun and ordered him to kill Brian as his initiation into the Cobra gang. Unable to cope with the grief, Brian's mother takes the gun that Roger recently bought and shoots Torres as he is being escorted out of the police department. Guest stars Leslie Hope, Dean Cain. [Edit]