Mexican prosecutors accuse Mr Salas of being the man tasked with guarding Joaquin Guzman, the fugitive leader of the Sinaloa cartel.

BBC: Shorty Guzman's 'security chief' arrested in Mexico

Joaquin Guzman, known as "El Chapo", or "Shorty", was arrested in 1993.

BBC: Shorty Guzman's 'security chief' arrested in Mexico

But their control over this territory is now said to be facing a challenge from their former allies, the Gulf Cartel, in an alliance with the Sinaloa cartel led by Joaquin Guzman, Mexico's most wanted man.

BBC: Seventeen partygoers shot dead in Mexico