Mexican authorities say they have arrested the top money launderer for the Mexican drug lord Joaquin Guzman, known as "El Chapo" or "Shorty".
Juan Manuel Alvarez Inzunza, nicknamed "King Midas", was detained while on holiday in the southern state of Oaxaca.
Guzman, a former leader of the Sinaloa cartel, is currently awaiting extradition to the United States.
He was recaptured in January after breaking out of a high-security prison.
Mr Inzunza is suspected of laundering $300m-$400m a year for the Sinaloa cartel through a network of companies and currency exchange centres.
A US federal court in Washington had requested Mr Inzunza's arrest and he is likely to be extradited.
Guzman himself is also facing extradition to the US on charges of drug trafficking in California, and murder in Texas.
Earlier this month, he asked for the extradition process to progress rapidly so he could receive better treatment in prison.
Since Guzman's recapture in January, six months after he escaped from prison, he has been subject to a stricter regime.