Harper Dearing

Harper Dearing was the main antagonist of Seasons 9-10 of the hit TV show, NCIS. He is protrayed by Richard Schiff. He was a terrorist responsible for the fire bombing of several Navy ships as well as the fatal attack on the Navy yard which left a number of people dead as well as the survivors tramatized. He also taunted the NCIS team for months bombing. His motivation for these attacks was the tragic death of his son due to an accident on a ship involving faulty wiring.

Pre-NCIS
Dearing was once happily married and served as the CEO of a major company until his son was killed in said ship accident after a practical joke went arry. Harper's mind then took a turn for the worst as he began getting into trouble with the law which resulted in him getting divorced which sent him over the edge and he began plotting terrorist attacks against the Navy.

Season 9
To do this, he aquired the Watcher fleet microchip, which was formerly used by the now defunct anti-terrorist team, Phantom Eight, via a secret auction. He repeatedly attempted to both kill NCIS agents and destroy Navy ships but largely failed due to them stopping the fires set by the arsonist he hired to so his dirty work. He eventually became the most wanted terrorist in the U.S. NCIS eventually tries to recruit former antagonist, Johnathan Cole to sell his services to Dearing. Unfortunately, Dearing saw right through this and retaliated by using Director Vance's car to hide a large bomb which destroyed the NCIS building and left many people dead or injured.

Season 10
At the beginning of Season 10, following the attack on NCIS, Dearing is lured to a hotel romm by a woman named Lorrain. Lorrain tures out to be an FBI who then attempts to assassinate Dearing but again, he slips right trap, blowing up the hotel room and earning the revenge of the FBI. Dearing goes so far as to bribe a judge to release Gibb's girlfriend's abusive ex-husband. At this point, he call Gibbs in MTAC but allows himself to be traced and blows up the car he is seemingly in. NCIS finds a charred corpse and at first it seems to be Dearing but Gibbs was not convinced and the body is eventually revealed to be Dearing's deceased brother. Gibbs realizes where Dearing would be hiding and drives to an empty house where Evan was born. After Dearing talks with an indifferent GIbbs, he walks towards the window where a gun was waiting, Dearing grabs it but Gibbs stabs Dearing to death first, ending the villain's reign of terror for good.