Mexico's navy on Friday captured Rafael Caro Quintero, the drug lord convicted of murdering a US anti-narcotics agent in 1985, and whose story was dramatised in crime drama Narcos: Mexico.
His arrest came at a severe price, however, when a helicopter used in the mission crashed, killing 14 military personnel.
Marines flushed out Caro Quintero with a bloodhound in a far-flung corner of the northwestern state of Sinaloa, one of Mexico's drug-trafficking heartlands, before the Black Hawk helicopter came down as it was about to land further south.
Caro Quintero rose to prominence as a co-founder of the Guadalajara Cartel, one of Latin America's most powerful drug trafficking organisations during the 1980s, and had been among the most prized targets for US officials.
The US government hailed the arrest and said it would waste no time in requesting his extradition.
"This is huge," White House senior Latin America adviser Juan Gonzalez said on Twitter.
Caro Quintero was captured in San Simon in the Sinaloa municipality of Choix after the military-trained female bloodhound named Max found him in shrub land, the navy said.
The arrest comes after pressure from the United States, according to a Mexican official, and the same week that President Andres Manuel Lopez Obrador met with US President Joe Biden in Washington.
Lopez Obrador said on Twitter the navy would investigate what caused the helicopter to crash in the city of Los Mochis, Sinaloa, that killed 14 and left one seriously injured. He said it had been carrying military personnel who were backing up the team that arrested the kingpin.
Caro Quintero spent 28 years in prison for the brutal murder and torture of former US Drug Enforcement Administration agent Enrique "Kiki" Camarena, one of the most notorious killings in Mexico's bloody narco wars. The events led to a nadir in US-Mexico co-operation during a five-decade "war on drugs".
Caro Quintero has previously denied involvement in the killing of Camarena. He was released in 2013 on a technicality by a Mexican judge, embarrassing the previous government.
He quickly went underground and returned to trafficking as part of the Sinaloa Cartel, according to US officials, who put him on the FBI's Top 10 most wanted fugitives list and put a $20 million bounty on his head, a record for a drug trafficker.
Last year, he lost a final appeal against extradition to the United States. He will be extradited as quickly as possible, another Mexican official said.
"It is probably one of the most important captures of the last decade in terms of importance to the DEA," said Mike Vigil, the DEA's former chief of international operations.
US Attorney General Merrick Garland said he would seek Caro Quintero's immediate extradition.
"There is no hiding place for anyone who kidnaps, tortures, and murders American law enforcement. We are deeply grateful to Mexican authorities for their capture and arrest of Rafael Caro-Quintero," Mr Garland said.
Before extradition, Caro Quintero will be held in Altiplano prison in the state of Mexico, Mexican prosecutors said. The penitentiary is notorious as the one from which his old Sinaloa Cartel associate Joaquin "El Chapo" Guzman escaped in 2015.
While the 69-year-old Caro Quintero is no longer considered a major player in international drug trafficking, the symbolic impact of his capture is significant.
The arrest points to significant co-operation between the US and Mexico despite recent clashes over security, said Mexican security expert Alejandro Hope. "This type of capture is unthinkable without the participation of the DEA," he said.
Mexico's unwillingness to extradite Caro Quintero to the US before his release from prison had been a source of tension between the two countries. A US official said Washington was very eager to have him extradited.
"This will hopefully start to mend the frayed relationship between the United States and Mexico in terms of combating drug trafficking," said former DEA official Vigil.
