Eduardo Arellano-Felix, the last of four brothers who ran the drug cartel in Mexico known as the Arellano-Felix Organization, was sentenced Monday to 15 years in U.S. federal prison for his role as chief financial officer, the U.S. Department of Justice announced.

Arellano-Felix, 56, was sentenced after pleading guilty in May to charges of conspiracy to launder money and to use and invest illicit drug profits.

A medical doctor known as "El Doctor," Arellano-Felix used drug-trafficking proceeds to pay members of the drug cartel to commit crimes, buy firearms, pay bribes and purchase drugs, according to the plea agreement.