Colonel Merton Bell was a villain from the TV show NCIS. He was a former tank commander who, after leaving the army, founded and led a mercenary firm, First Defense PMC, the largest in the US.
After spending two months in a Mexican prison thanks to the actions of NCIS Special Agent Leroy Jethro Gibbs, Bell started to plan his revenge aided by M. Allison Hart, his lawyer, and Paloma Reynosa, who was the head of the Reynosa drug cartel and also had a grudge against Gibbs. In the final episodes of Season 7, Bell started to make his move against Gibbs and sent one of his men, Lieutenant JP Dean, to kill Special Agent Lara Macy before gathering his men to go to Mexico and kill Mike Franks and his family.
During the shootout between Franks and Bell's men, several of the cartel's men arrived. Paloma had sent them to capture Franks as leverage against Gibbs and to kill Bell, whom she no longer needed. Dean, who had been turned by Paloma, killed Bell, and Bell's head and hands were cut off -- presumably, by cartel members under Paloma's orders. Dean later admitted to being responsible for killing Bell, but not for mutilating his corpse.
Bell's body (minus head and hands) was returned to Washington D.C., where Dr. Mallard performed the autopsy, which revealed that Gibbs's SIG Sauer had been used to shoot Colonel Bell, but the bullets were delivered post-mortem. Gibbs, therefore, was innocent of Bell's death; someone else had shot Bell's dead body with his SIG in an attempt to frame him.