Arturo Guzmán Decena (13 January 1976 – 21 November 2002), also known by his code name Z-1, was a Mexican Army Special Forces officer and high-ranking member of Los Zetas, a criminal group based in Tamaulipas.

He defected from the military in 1997 and formed Los Zetas, the Gulf Cartel's former paramilitary wing, under the leadership of the kingpin Osiel Cárdenas Guillén.

He served as the right-hand man of Cárdenas Guillén until 21 November 2002, when he was gunned down and killed by the Mexican Army Special Forces in the border city of Matamoros, Tamaulipas.

[4][5] His talents and aggressive behavior earned him a position with an elite Mexican military group called Grupo Aeromóvil de Fuerzas Especiales (GAFE), originally trained in counter-insurgency tactics for the Zapatista uprising in 1994 and for locating and apprehending members of Mexico's drug trafficking organizations.

The rebellion was a symbolic rising against poverty and the single-party rule of the Institutional Revolutionary Party (PRI), and many rebels took arms; the Mexican government, however, sent in the GAFE to put down the Zapatistas.

[7] Mounting pressures arose from the families of the "disappeared" who made marches in Mexico City, and many military officers were found guilty in courts-martial for human right abuses and corruption.

For years, some military generals took bribes from the cartels; amid the turmoil, Guzmán Decena acknowledged that he was better off outside the system and as a leader of Los Zetas.

Within some months, Guzmán Decena commanded a mercenary army of 38 defected soldiers enticed by salaries substantially higher than those paid by the Mexican government.

[9] The GAFE soldiers that went to work with the Gulf cartel took with them a number of the Mexican Army's most sophisticated machine guns, assault rifles, pistols, bazookas, grenades, and telecommunications and surveillance equipment.

[10] The role of Los Zetas was soon expanded by "collecting debts, securing cocaine supply and trafficking routes known as 'plazas,' and executing its foes – often with grotesque savagery.

[12] At first, both of them functioned well together: they bought off police officers, bribed politicians and soldiers, and managed to take control of major drug shipments coming in from Guatemala.

For killing Gómez Herrera, Cárdenas Guillén earned his nickname, the Mata Amigos ("Friend Killer"), and Guzmán Decena, the trust of his boss.

[15][16] Another account written by Jesús Blancornelas indicates that Guzmán Decena went to a restaurant, had a few strong drinks, snorted a line of cocaine, and then decided to visit his mistress Ana Bertha González Lagunes, who lived a few blocks away.

[19] In an apparent revenge for Guzmán Decena's assassination, four members of the Office of the General Prosecutor were abducted and murdered near Reynosa, Tamaulipas in early 2003, allegedly by Cárdenas Guillén's men.