Living in the United States, he also became a jeweler and precious metals broker until he began selling cocaine in New York City.

Herrera also ran one of the "most sophisticated and profitable money laundering operations", according to the United States Drug Enforcement Administration.

[5] The Herrera operation, according to the DEA, involved importing cocaine base from Peru and Bolivia, which was then trafficked via his own transportation to conversion laboratories in Colombia.

It is believed that Herrera hired guerrilla forces such as Fuerzas Armadas Revolucionarias de Colombia (English: Revolutionary Armed Forces of Colombia) (FARC) and then guerrilla group 19th of April Movement (Spanish: Movimiento 19 de Abril, M-19), to guard remote lab sites.

[7] Another attempt on Herrera's life was made on July 27, 1991, in a summer resort: hooded gunmen wearing pink bracelets opened fire, killing 17 and hurting 13 others.

In addition, records of transactions and personnel were seized from computers, which information later provided a greater look into the Cali Cartel cell structure.

[9] On September 1, 1996, Herrera turned himself in to the Search Bloc (Spanish: Bloque de Busqueda), a unit of the Colombian National Police.

These declarations, however, the police investigating the murder found this story unreliable, and newspaper articles at the time suggested it was a stratagem to take attention away from the real masterminds.