The Rastrojos are one of Colombia's most powerful drug trafficking organizations, working closely with international partners, such as the Sinaloa Cartel, sending drug shipments from Colombia to Central America and Mexico, bound for the United States.
A longtime hitman who rose through the ranks of the Norte del Valle Cartel (NDVC), Perez specialized in collecting coca in rural areas and setting up laboratories to turn it into cocaine. He soon came the attention of Wilber Varela, one of the leaders of the NDVC. When Varela began a war with a rival member of the NDVC, Diego Montoya, alias "Don Diego," he turned to Perez to set up a private army and named it after his underworld alias, "Rastrojo." In 2002 the Rastrojos were born and Perez led the war against Montoya's private army, called the "Machos," a war which he ended up winning.
The other rising star in Varela's organization was Javier Calle Serna, alias "Comba." Perez supported Comba when he killed Varela in 2008 and took command of the whole organization, which then became known to all as the Rastrojos.
Perez was instrumental in the expansion of the Rastrojos from 2008 onwards, sending out heavily armed cells to different parts of the country, in order to secure access to drug crops, protect cocaine laboratories and control internal movement corridors within Colombia. It was Perez who negotiated an alliance with rebels of the National Liberation Army (ELN) in the provinces of Cauca and Nariño on the Pacific coast. This later developed into a nationwide alliance in the interests of drug trafficking, with the ELN selling coca base to the Rastrojos in not only Cauca and Nariño, but also Antioquia, Choco, Bolivar and Norte de Santander.
Rumors surfaced of his arrest in January 2011 in Venezuela, but they quickly proved false. He always maintained a very low profile, and very little was known about him. He was believed to be continuously on the move, both inside and outside of Colombia. He maintained direct command over many of the different Rastrojos units across the country, and takes a direct hand in fighting, and eliminating, rivals.
With the surrender of Comba US authorities to the US Drug Enforcement Administration (DEA) on May 8, 2012, Perez was the favorite to assume overall command of the Rastrojos until his eventual capture.