With the daring nighttime capture of the Zetas drug cartel leader, the Mexican government has delivered a major blow to the country's most vicious gang, known for beheadings and massacres of migrants.
Capturing Miguel Angel Trevino was the biggest anti-cartel victory for the administration of President Enrique Pena Nieto since he took office in December with his pledge to reduce a wave of drug-related murders that has left 70,000 people dead since 2006.
With this high-profile catch, Pena Nieto provides a rebuttal to fears that his new security strategy focused too much on crime prevention instead of putting kingpins in handcuffs.
But the arrest of Trevino, a drug kingpin who authorities say would "stew" his victims in burning oil, could set off an internal war of succession marked by more strife in the cartel's northeastern territories, analyst say.
Sinaloa drug cartel kingpin Joaquin "El Chapo" Guzman, whose dominion covers the Pacific coast, could also see Trevino's demise as the perfect opportunity to raid the regions dominated by the Zetas.
Interior ministry spokesman Eduardo Sanchez said authorities were on "alert" for any rise in violence following Trevino's arrest.
"There are two scenarios," Raul Benitez Manaut, security expert at the National Autonomous University of Mexico (UNAM), told AFP. "The positive one is that the cartel is weakening, and the negative is that there could be a war between subordinates and much violence."
Trevino, alias "Z-40," was intercepted by marines before dawn on Monday after a helicopter swooped down in front of his pick-up truck as he traveled with two associates on a dirt road near Nuevo Laredo, a northeastern city in the state of Tamaulipas, which borders Texas.
The Mexican and US governments have not said whether the United States helped catch Trevino. His arrest came days after the head of the US Drug Enforcement Administration (DEA) visited Mexico and amid a visit by the Mexican military chiefs in the United States.
Trevino's arrest came eight months after Mexican troops killed his predecessor, Heriberto Lazcano, in a gunfight in the northern state of Coahuila, only for the capo's body to be stolen by gunmen hours later in a funeral home.
Lazcano's death was not followed by internal bloodshed for his job, but analysts say it remains to be seen if Trevino's capture will lead to an orderly succession or a fight.
His brother Omar "Z-42" Trevino is considered a potential heir, but it is unclear how high up he ranks within the organization. The Zetas were formed by former elite soldiers and its leaders had been ex-troops until Trevino, a civilian, took over last year.
"Omar could step in and take power relatively quickly. Or someone within the Zetas could see this as an opportunity to step in and there could be infighting," said Sylvia Longmire, a former US Air Force special agent and author of "Cartel: The Coming Invasion of Mexico's Drug Wars."
But she said Trevino's arrest may not affect the cartel's day-to-day operations because the Zetas work like a franchise, with each cell overseeing its own turf. At the same time, however, rival gangs could smell blood.
"El Chapo could say this is a perfect, opportune time to strike while there's a leadership void. This leaves lots of opportunities for an increase of violence in the short term," she told AFP.
Stratfor, a Texas-based security consultancy, said an internal power struggle could ramp up violence in eight northern and Gulf of Mexico states where the Zetas have a substantial presence.
Gerardo Rodriguez, a private national security consultant, said the leadership switch could actually bring peace to the "plazas," or territories, controled by Zetas cells because they will feel less pressure from Trevino, who was considered one of the most violent drug capos in Mexico.
Trevino is accused of ordering the kidnapping and killing of 265 Central and South American migrants.
"A possibility is that the new leadership will be more sophisticated and will get rid of this strategy of extreme violence, which was the reason they were targeted by the US and Mexican governments and other criminal organizations," Rodriguez said.