Mark Harmon played the role of Special Agent Leroy Jethro Gibbs on ‘NCIS’ for years, and he helped solve numerous crimes ranging from murder to Espionage.
In season 19, episode 4 of the series, an FBI agent was in search of Harmon with a warrant for his arrest.
Later on, the FBI agent found out that Harmon had gone on a separate mission to capture a serial killer in Alaska. It was in this episode that the producers first hinted that Harmon would not be returning to the series.
Another indication that Harmon was leaving the show, was when he had a sit-down with Ducky and Torres.
Harmon explained to Ducky that he had been going through a difficult phase, and he’s still searching. In another scene, Torres drove Harmon to the airport and they said their goodbyes with a hug.
For a while in the series, a serial killer was responsible for mysterious deaths, and Harmon took it on himself to solve them.
Harmon and hi team later figured out who hired the serial killer in the first place.
When the FBI agent, Parker, came to arrest Harmon, he managed to persuade him to love his lat murder case, then he would be taken into custody.
Vance disclosed to Torres that Harmon was done with the job, and that he tried to persuade him to stay, but could not get through.