Drug kingpin Hernan Alonso Villa, accused of running a Narco-trafficking gang in Columbia that has killed over 400 people, was arrested in Spain on July 19.

Known as “El Ratón” or “The Rat” in Spanish—but most often translated as “The Mouse” by media sources—Villa’s organization, La Oficina de Envigado, inherited the business of the Medellin cartel, the now-defunct cocaine empire set up by Colombian drug lord Pablo Escobar.

Police in the Spanish region of Alicante said Saturday that they had arrested a 40-year-old man whom they identified as the head of the military wing of La Oficina de Envigado and one of Colombia's most wanted criminals. "El Ratón was arrested thanks to the work of our people and the Spanish authorities," said Rodolfo Palomino, the Colombian chief of police. "Villa committed serious crimes in Medellin, in particular  murders, disappearances, extortions and kidnappings. He then went to Europe seeking to continue his activities in drug dealing and coordinating trafficking routes."

The former left-wing guerrilla Diego Murillo Berajano, or Don Berna, established La Oficina de Envigado in the 1980s to be Escobar's muscle and to meet the Medellin Cartel’s growing demand for paid assassins. When Escobar was killed in 1993, this hodgepodge of killers took over much of his empire. La Oficina de Envigado is now a loose-knit patchwork of smaller organizations that has sought alliances with street gangs to keep control of the drug trade.

Arrested in a joint operation with Colombian police, Villa has been accused of homicide, forced displacement, and manufacturing and carrying illegal weapons. The Spanish police ministry explained how "he took a number of security measures in an attempt to avoid arrest, including constantly changing addresses, changing telephones and using different false identities…He had more than 200 people under his command and was responsible for exporting cocaine to Spain, the United States and Holland.”

According to the Spanish ministry, Villa was caught with more than $50,000 in cash when he was arrested. He will be subject to an extradition order by the Colombian police. Spain is one of the main entry points for illegal narcotics into Europe for Columbian narco-traffickers. According to the United Nations Office on Drugs and Crime, Colombia produced 320 tons of cocaine in 2013.