The Reynosa Cartel is one of the most powerful Mexican drug cartels. It was led by Paloma Reynosa who took over command when her husband died.
In addition to being the leader, Paloma is also the daughter of Pedro Hernandez who is one of the cartel's most notable members as he was the one responsible for murdering Shannon Gibbs and her daughter Kelly Gibbs before he died at the hands of Leroy Jethro Gibbs.
Despite NIS's best efforts, Hernandez went after her and shot the NIS agent in the head, resulting in the agent's death while the car crash that happened due to the agent's death also causes Shannon and Kelly's deaths.
Gunnery Sergeant Leroy Jethro Gibbs, the husband and father of Shannon and Kelly, respectively, returned from Iraq badly wounded to find his family dead but Hernandez fled to Mexico to avoid being caught.
Despite NIS Special Agent Mike Franks's attempts, the Federales refused to extradite him back to the US. Special Agent Franks allowed a vengeful Gibbs to discover Hernandez's location. He then tracked him down to Mexico and just as Hernandez was driving home in his pickup truck, Gibbs used a round from his M40A1 sniper rifle to shoot Hernandez in the head, the impact of which killed Hernandez instantly.
As a result, Gibbs later returned to the U.S and soon resigned from the Corps, becoming an NIS/NCIS Special Agent while keeping the crime hidden for nearly twenty years.
By 2010, the cartel had become increasingly powerful and the new head was Paloma Reynosa, wife of the deceased head of the cartel. In the episode Mother's Day (episode), it was revealed that Navy Captain Joseph Norton had made $10 million by selling intelligence about US anti-drug operations in Mexico. Norton was killed in the U.S by Joann Fielding, Shannon Gibbs's mother and Gibbs's former mother-in-law, who wanted revenge against the cartel responsible for her daughter and granddaughter's deaths.
In the episode Borderland (episode), the Mexican government began working on a project for an international task force with the Americans to strike against the cartels, notably the Reynosa drug cartel.
Mexican Justice Department official Alejandro Rivera was tasked with setting up the task force and asked Abigail Sciuto, NCIS's forensic scientist, to train a class of task force officials in Mexico.
For their forensic training, Rivera assigned them the cold case on Hernandez's death and, after much digging, she discovered that Gibbs had killed Hernandez with the revelation stunning her. She eventually confronted Gibbs over her discovery and the two soon concluded that someone was trying to discover who was behind this reopening of the case.
It was subsequently revealed that Alejandro Rivera was Paloma Reynosa's brother and the son of Pedro Hernandez. It was Paloma Reynosa and Alejandro Rivera who had orchestrated the reopening of the case after learning of Colonel Merton Bell's vendetta against Agent Gibbs. Reynosa secured the services of Jason Paul Dean, who killed NCIS Special Agent Lara Macy and Colonel Bell, along with several of his associates. Dean also maimed Mike Franks and captured Agent Gibbs. However, Jason Paul Dean was later tracked down and killed in a shootout with NCIS Special Agents Anthony DiNozzo, Timothy McGee, and Ziva David.
Following the shootout, NCIS Director Leon Vance ordered DiNozzo to Mexico to surreptitiously place Alejandro Rivera under surveillance and report his movements. Special Agent DiNozzo was intercepted by Franks, whose intent was Rivera's elimination. Rivera, aware of DiNozzo and Franks, attempted to ambush and kill them both. DiNozzo escaped unharmed but Franks was seriously injured and required several months of recovery.
On May 25th, on the same year, Paloma Reynosa had traveled to Stillwater to kill Gibbs` father, Jackson Gibbs, where she confronted him, starting a short gun fight between the two. Four months later, Alejandro Rivera, believing his sister to be dead, opened fire on a safe house that he believed Gibbs, Jackson, and Mike Franks to be housed inside.
However, after seeing that Gibbs, his father, and Franks, were not inside the safe house, Alejandro was shown inside only to see a dying Paloma on the floor. Within a few minutes, Paloma Reynosa was dead, and Alejandro was placed under arrest for several murders.
After Paloma's death, the Cartel remained operational. Alejandro Rivera, despite being in prison, told the Cartel to contact his associates in the Mexican government which allowed the Cartel to grow strong again. By 2014, they were still operational but then Alejandro Rivera joined his cartel with the defunct group the Brotherhood of Doubt. When Alejandro's girlfriend gave up information to Special Agents Bishop and McGee the cartel became inactive again and the brotherhood destroyed in an air strike on their compound.
- Pedro Hernandez- The original leader of the Cartel who died after being shot in the head by Leroy Jethro Gibbs.
- Paloma Reynosa- Hernandez's daughter who became the leader after her unnamed husband died. Later died at the hands of her brother, Alejandro Rivera.
- Alejandro Rivera- Hernandez's son and Paloma's brother. A Mexican Department official, Rivera was arrested after accidentally killing his sister.
- Jason Paul Dean- A disgraced Army Ranger who was originally a member of Colonel Merton Bell's team before joining the Reynosa Cartel. Is responsible for the deaths of Bell and Special Agent Lara Macy. Died after being shot by NCIS Special Agent Tony DiNozzo.
- Joseph Norton- A Navy Captain who made money by selling intelligence concerning U.S anti-drug operations. Was killed by Joann Fielding, Leroy Jethro Gibbs's mother-in-law.
- David Shankton- A Navy Officier who made money smuggling drugs from Mexico to the U.S. with Norton's help. Was framed by Joann for killing Norton and sent to prison.
- Ray Collins- A Marine Corporal working as a hitman who's responsible for killing 10 American drug dealers. Was killed in self-defense by Velvet Road, made to look like one of Collin's other murders.
- Numerous unnamed Reynosa Cartel henchmen.
- Unnamed marine - (shot to death by Pedro).
- The car shooting (three fatalities; committed by Pedro):
- Kurt Mitchell - (shot from long range with a sniper rifle)
- Shannon Gibbs - (died in car crash with her daughter after the agent was killed).
- Kelly Gibbs
- Martin Hendricks - (baked to death by cartel hitmen)
- Ray Collins' hits
- Mark Jenloe
- Douglas Johnson
- Robert Chadway
- Alan Sandich
- Anthony Jones
- Stuart Mayne
- Jeffery Anderson
- Richard Brown
- Karl Killian
- Kevin Young
- Velvet Road- (Poisoned, attempted to kill but she survived and killed him in self-defense).
- Special Agent Lara Macy- (stabbed to death, then set on fire by Jason).
- The Mexico shootout (four fatalities):
- Colonel Merton Bell- (shot in the back and then decapitated post-mortem by Jason).
- Matthew Moore
- Anthony Jones
- Douglas Williams
- John McMann (shot to death by Paloma)
- Charles Newberg (shot to death by Paloma)
- Unnamed NCIS agent (shot to death by Paloma)
- Gunman (shot to death by Paloma)
- Paloma Reynosa (shot to death by Alejandro)