Jan 15 - A witness at the U.S. trial of Joaquin 'El Chapo' Guzman testified on Tuesday that he previously told U.S. authorities that the accused Mexican drug lord once paid a $100 million bribe to former Mexican president Enrique Pena Nieto. Alex Cifuentes, who has said he was a close associate of Guzman for years, discussed the alleged bribe under cross-examination by one of Guzman's lawyers in Brooklyn federal court. Asked if he told authorities in 2016 that Guzman arranged the bribe, he answered, 'That's right.'