Mexican police and soldiers on Wednesday arrested the man widely considered to be the most important leader of the Zetas drug cartel, Omar Trevino Morales, a federal official said.
The official, who was not authorized to be quoted by name due to government policy, said the man known as "Z-42" was arrested in a pre-dawn raid in San Pedro Garza Garcia, a wealthy suburb of the northern city of Monterrey.
The Mexican government had offered a 30-million peso ($2 million) reward for his capture on weapons and organized crime charges.
The US Drug Enforcement Administration had offered a $5 million reward for his capture, saying he was wanted on drug-trafficking charges, but listed "Omar" as an alias and his given name as Alejandro.
The suspect is the brother of Miguel Angel Trevino Morales, described as the most bloodthirsty leader of Mexico's most violent cartel.
Miguel Angel was arrested in July 2013, almost a year after marines killed the Zetas' other biggest leader, Heriberto Lazcano "El Lazca."
The Zetas carved a path of brutality, bloodshed and mutilated bodies across northern Mexico during their turf battles with the rival Gulf cartel.
Much of the violence along Mexico's northeast border, however, is now due to internal battles among factions of the Gulf cartel.
The capture of Omar Trevino Morales comes just a few days after Friday's arrest of another big cartel leader, Servando Gomez, alias "La Tuta." Gomez allegedly led the Knights Templar, a pseudo-religious drug gang that built up control of many sectors of the economy in the western state of Michoacan.
Like Gomez, Omar Trevino Morales was captured without any shots being fired.
The Trevino Morales brothers took proceeds from drug sales in the United States and laundered them by purchasing American quarter horses. That scheme was led by Jose Trevino Morales, a third brother. A jury in Texas found Morales guilty in May of investing $16 million of drug money in the buying, training and racing of horses across the Southwest.