By Sonia Moghe, Maria Santana and Ray Sanchez, CNN

(CNN) -- A former close personal aide to Joaquin "El Chapo" Guzman testified Tuesday that the drug kingpin once paid a $100 million bribe to former Mexican President Enrique Peña Nieto.

The stunning testimony came from Alex Cifuentes, a Colombian trafficker who once served as Guzman's secretary and close personal aide.

After three days on the stand in the Brooklyn federal courtroom, the bombshell revelation was only brought up in court by defense attorney Jeffrey Lichtman, not prosecutors.

Representatives for Peña Nieto have not responded to a CNN request for comment.

Cifuentes had been testifying about two years spent living with Guzman in the mountains of Sinaloa as the fugitive kingpin eluded the army.

While previous testimony implicated lower-level Mexican politicians as well as police and military officials in the vast corruption network that facilitated Guzman's cartel's trafficking, Tuesday's accounts struck at the highest levels of Mexican political life.

There is a chance jurors may get to hear from Guzman himself during the trial -- Lichtman revealed in court that Guzman is being listed as a potential defense witness. But that doesn't mean his attorneys are required to call on him to testify. The move gives prosecutors a chance to prepare in the event that he chooses to do so.

Details of the alleged bribe

Under cross examination by defense lawyer Lichtman, who referred to transcripts of de-briefings Cifuentes had with US authorities, Cifuentes alleged that a $100 million bribe was paid to Peña Nieto, who was President from 2012 to 2018.

During opening statements in November, Lichtman claimed that Peña Nieto and former Presidents of Mexico "received hundreds of millions of dollars in bribes from his organization."

A spokesman for Peña Nieto at the time denied the accusation in a statement posted on Twitter.

"The government of Enrique Peña Nieto persecuted, captured, and extradited the criminal Joaquin Guzman Loera," the statement said. "The accusations made by his lawyer are completely false and defamatory."

On Tuesday, Lichtman asked Cifuentes about statements he made to US officials in November 2017, when he claimed the former President allegedly contacted Guzman to say he "didn't need to stay in hiding" if he paid the money.

Cifuentes told authorities the money was given to Peña Nieto in October 2012, when he was president-elect.

"Yes, that very thing is what Joaquin told me," Cifuentes responded, adding that a bribe would ensure the kingpin could "continue working."

Cifuentes said in three separate meetings with US authorities, in 2016 and 2017, that $100 million was paid to Peña Nieto. In a September 2018 meeting, his story changed. He told prosecutors he had been confused about the exact amount of payment.

On Tuesday, he testified that he was "confused" about the exact amount of the bribe.

In one debriefing with the US, Lichtman said Cifuentes told US authorities that a woman who worked for political strategist JJ Rendon sent the witness pictures of suitcases filled with cash inside Rendon's personal plane. Rendon was running Peña Nieto's campaign at the time.

Cifuentes said he believed the photos of cash-filled suitcases were taken in Mexico City.

Rendon denied Cifuentes' allegations in an interview with CNN Español on Tuesday, and said he is willing to be investigated for them.

Lichtman also asked Cifuentes about another claim he made to US authorities in 2016: that former President Felipe Calderón received a bribe from a rival drug trafficking family.

In November, Calderón denied that he ever received any payments. "The claims made by Joaquin 'El Chapo' Guzman's lawyer are absolutely false. Neither he nor the Sinaloa cartel nor anyone else made any payments to me," he wrote on Twitter.

In court Tuesday, Cifuentes said he did not recall this incident.

Cifuentes, who described himself as Guzman's "right-hand man, his left-hand man," had testified earlier Tuesday that Guzman had attempted a $10 million bribe to another high ranking Mexican official but was turned down because the official disliked Guzman.

Cifuentes took the stand against his former boss on Thursday, sharing details on Guzman's trafficking operations and how the head of the Sinaloa cartel evaded authorities in a series of remote mountain hideaways in his home state.

Cifuentes was arrested in Mexico in 2013 and later extradited to the United States, where he pleaded guilty to drug trafficking charges and entered a cooperation agreement with the US government.

Guzman, 61, has pleaded not guilty. If convicted of international drug trafficking, conspiring to murder rivals, gun charges and money laundering, he faces a sentence of life in prison.

In 2017, Guzman was extradited aboard a flight from Juarez, Mexico, to New York.