Rafael Caro Quintero, once one of Mexico's most powerful drug traffickers, has been added to the FBI's 10 Most Wanted List.

Caro Quintero was jailed in 1985, but released in 2013 and remains on the run despite efforts to recapture him.

The US and Mexico think he's still a high-ranking cartel member, but he denies it and others doubt it as well.

In a joint announcement with the US Drug Enforcement Administration, the US Marshals, and the State Department, the FBI said on Thursday that it would add fugitive Mexican cartel kingpin Rafael Caro Quintero to its Top 10 Most Wanted list.

"He's considered one of the Mexican godfathers of drug trafficking. He helped to form the Guadalajara cartel in the late 1970s, and he became one of the primary suppliers of heroin, cocaine, and marijuana to the United States," an FBI official said during the announcement. "He was also in charge of the cartel in Costa Rica and along the US-Mexico border."

The FBI is offering $20 million for information leading to his capture — "one of the highest rewards in the history of the program."

Caro Quintero is currently one of the DEA's three top wanted fugitives, a designation he shares with Ismael Zambada Garcia, who is thought to be the current leader of the Sinaloa cartel, and with Nemesio Oseguera-Cervantes, leader of the Jalisco New Generation Cartel. The CJNG and Sinaloa are considered Mexico's two most powerful cartels.

Caro Quintero, nicknamed "the prince" and "the narco of narcos," was one of three leaders of the Guadalajara cartel, which dominated the Mexican drug trade in the 1970s and 1980s. The cartel was undone by the February 1985 kidnapping and killing of undercover DEA agent Enrique "Kiki" Camarena in the western Mexican city of Guadalajara.

Camarena's body and that of a pilot were found about a month later, buried in a shallow grave. Camarena showed signs of extensive torture. His abduction and killing caused a firestorm in US-Mexico relations. The US came close to shutting the border. President Ronald Reagan pressured Mexico's president at the time, Miguel de la Madrid, to act.

FBI

Caro Quintero and another Guadalajara kingpin, Ernesto Fonseca, were caught before the end of 1985. (The other, Miguel Angel Felix Gallardo, wasn't captured until spring 1989.) Caro Quintero was convicted and sentenced to 40 years in prison. In the years after their arrests, the Guadalajara cartel split, and from it emerged, among others, the Sinaloa, Tijuana, and Juarez cartels, which have dominated Mexico's drug trade in the years since.

In 2013, after 28 years in prison, Caro Quintero's conviction was overturned on a technicality. A higher court soon reversed that decision, but he had gone into hiding and remains free.

Caro Quintero "wants to remain under the radar," said Mike Vigil, former chief of international operations for the DEA. "He is going to keep a very low profile."

The fugitive drug lord knows "he's old and he's not in good health and he will die in prison if he gets caught," said Vigil, who worked undercover in both Mexico and Colombia.

Rafael Caro Quintero, during an interview with Proceso in July 2016. Proceso

Mexican officials said in mid-2016 — several months after Sinaloa cartel chief Joaquin "El Chapo" Guzman was captured — that Caro Quintero had emerged and partnered with factions trying to take advantage of an apparent moment of weakness for the Sinaloa cartel.

While Caro Quintero has remained out of reach of authorities, he has surfaced to give interviews, denying continued involvement in the drug trade and asking for mercy.

"I was a drug trafficker 31 years ago, and from that moment I am telling you that when I lost the crops from" the Buffalo Ranch in Chihuahua state, where Camarena led authorities to a multibillion-dollar marijuana marijuana in 1984, "there I ended that activity," Caro Quintero told Mexican journalist Anabel Hernandez in a 2016 interview.

"Never have I exercised it [since] and I'm not going to do it," he said at the time. "I stopped being a drug trafficker and I say to you again: Please, leave me in peace."

In that same interview, he said he did not kill Camarena, recanting an earlier confession, and asked forgiveness from Mexico, the DEA, and the US government. "I am not at war with anyone; El Chapo and El Mayo are my friends," he said, referring to Guzman and Zambada.

The DEA's 2017 National Drug Threat Assessment, published in October, also named Caro Quintero as one of the Sinaloa cartel's still-free leaders, alongside Zambada.

"Today, he's a top leader in the Sinaloa cartel, considered the largest drug-trafficking organization in Mexico, responsible for smuggling hundreds of tons of methamphetamine, marijuana, and cocaine into the United States," the FBI said during the announcement.

According to a 2018 interview with Hernandez, he remains on the run somewhere in northern Mexico, constantly moving and refusing even to have prostate surgery, fearing that a hospital stay will leave him vulnerable to arrest.

Ten hectares of a marijuana plantation seen after the Mexican army found it while patrolling in Mocorito, in Mexico's Sinaloa state, Mexico February 4, 2017. Thomson Reuters

"He'll often wake his guards before daybreak because he thinks someone is coming to arrest him," Hernandez says. "Some nights, they've had to walk perilous routes in the dark along the cliffs because he believed the authorities were closing in. More than once, Caro Quintero has taken a fall in the darkness."

Caro Quintero admitted having met with Zambada and Guzman after his release. "I have my respect for them and that's all. I haven’t done any business with them," he told Hernandez. "And now that I’m free, I don’t want to have anything to do with drugs."

The US and Mexico have accused Caro Quintero of smuggling cocaine from Colombia to the US, passing through Guatemala and Mexico. In March, Mexico sent troops to the Golden Triangle — a drug-producing region that covers parts of Sinaloa, Durango, and Chihuahua states — reportedly with orders "to catch him dead or alive."

But, Vigil said, Caro Quintero's current stature is likely much more modest than what is alleged.

"He's not the leader of the Sinaloa cartel. He's basically a shell of himself. His main preoccupation right now is to remain free," Vigil told Business Insider. "Money doesn't mean as much to him as freedom."