About NCIS Season 8, Episode 25 :

Having finally learned the identity of the Port-to-Port killer after the death of Mike Franks, Gibbs and his team prepare for the worst when he makes his final strike close to the heart of NCIS, leading Ziva into a trap. When Ziva is found by McGee, DiNozzo, Gibbs and Ray Cruz, she reveals that it was misdirection while the killer, Lt. Jonas Cobb, infiltrates NCIS to target the people he holds responsible for turning him into a killer as a part of "Operation Frankenstein": Leon Vance, Trent Kort and the Secretary of the Navy. Everything he has done since killing his first victim in Spain has been with the sole intention of finding them - but knowing that the Secretary of the Navy is under twenty-four hour protection, Cobb changes tactics and instead targets E.J. Barrett who is not only the person who has been investigating him from the beginning of his killing spree, but is also the Secretary of the Navy's niece. The NCIS team are able to track Cobb back to the facility where he was put through his training and is seen "training" Trent Kort, Jimmy Palmer and Barrett. He claims he only ever did what he thought was right, but refuses to surrender and is shot and killed by Gibbs and Vance. The Secretary of the Navy resigns over the affair, Trent Kort goes into hiding in Israel and Mike Franks is given a state funeral in a coffin built by Gibbs. The episode ends with DiNozzo being given a classified assignment to "handle" an unknown person and that an NCIS agent is suspected of selling classified information.