NEW YORK (NYTIMES) - Former Mexican president Enrique Pena Nieto took a US$100 million (S$135 million) bribe from Joaquin Guzman Loera, the infamous crime lord known as El Chapo, according to a witness at Guzman's trial.

The stunning testimony was delivered on Tuesday (Jan 15) in a New York courtroom by Alex Cifuentes Villa, a Colombian drug lord who worked closely with Guzman from 2007 to 2013, when the kingpin was hiding from the law at a series of remote ranches in the Sierra Madre.

"Mr. Guzman paid a bribe of US$100 million to President Pena Nieto?" Jeffrey Lichtman, one of Guzmán's lawyers, asked Cifuentes during cross-examination.

"Yes," Cifuentes said.

Guzmán may offer more details soon. Shortly after the jury was excused at around 4.30pm on Tuesday, Lichtman submitted his client's name to the prosecution as a potential witness for the defence, an indication that the drug trafficker might testify in his own trial.

Lichtman said that adding Guzman's name to the witness list does not guarantee that he will testify. It is simply "possible". "If I didn't put him on the list, it would possibly foreclose the possibility for him to testify," Lichtman said in an interview. "So, I was just being inclusive."

Guzman's testimony would be a stunning development. While his lieutenants have shared details about the Sinaloa cartel's operations, the kingpin himself could offer even more intimate information, such as how he possibly bribed a president of Mexico.

According to Cifuentes, Pena Nieto first reached out to Guzmán about the time he was elected president in late 2012, asking the drug lord for US$250 million in exchange for calling off a nationwide manhunt for him.

But Guzman made a counteroffer, Cifuentes added, saying he would give Pena Nieto only US$100 million.

"The message was that Mr Guzman didn't have to stay in hiding?" Lichtman asked.

"Yes," Cifuentes said, "that very thing is what Joaquin said to me." Lichtman, quoting Cifuentes' notes from an interview he gave to US authorities in 2016, asked whether Felipe Calderon, who preceded Pena Nieto as Mexico's president, took a bribe in 2008 from one of Guzman's rivals, the Beltran-Leyva brothers.

"I don't recall this incident very well," Cifuentes answered. He added moments later, "Right now, I do not remember that."

Pena Nieto and Calderon could not yet be reached for comment.

While other witnesses at Guzman's trial in US District Court in Brooklyn have testified about huge payoffs from traffickers to the Mexican police and public officials, the testimony about Pena Nieto was the most egregious allegation yet.

If true, it suggests that corruption by drug cartels had reached into the highest level of Mexico's political establishment.

After testifying about the two presidents, Cifuentes rattled off other bribes that Guzman and his allies had paid to Mexican officials. On at least two occasions, he said, the kingpin gave the Mexican military between US$10 million and US$12 million to launch operations to "either kill or capture" associates of the Beltran-Leyva brothers during his war with them.

Cifuentes also said the Mexican federal police not only turned a blind eye to drug trafficking, but occasionally took part in it. Once, he told jurors, traffickers gave the police photographs of several suitcases packed with cocaine that were sent by the cartel on an airplane from Argentina to Mexico. The police picked up the suitcases from the baggage claim, Cifuentes said, and sold the drugs themselves.

All of this came on Cifuentes' exhausting second day as a witness at Guzman's trial. He has already confessed to a staggering array of crimes.

On the stand, Cifuentes admitted to hatching a failed murder plot with the Hell's Angels in Canada. He acknowledged buying plastic explosives from the widow of a Honduran drug trafficker.

He said he paid a judge in Ecuador US$500,000 to throw out the case of an Ecuadorean military officer accused of working with the cartel, adding that he later helped kidnap the officer when it seemed that he was cheating Guzman.

There were lurid hints that top Mexican leaders might have been compromised by dirty money from the start of the trial in November. In his opening statement, Lichtman claimed his client had been framed for years by a conspiracy hatched by his partner, Ismael Zambada Garcia, in league with "crooked" US drug agents and a "completely corrupt" Mexican government, including two of its presidents.

At the time, Pena Nieto and Calderon released statements calling the accusations false. The judge in the case, Brian M. Cogan, later cautioned Lichtman against making promises to the jury that the evidence in the case would not support.

Then, as the first week of the trial came to an end, Guzman's lawyers informed Cogan at a sidebar conference that a coming witness, Jesus Zambada Garcia, Ismael Zambada's brother, would testify, if asked, that Mexican presidents had taken bribes from the Sinaloa drug cartel.

But Cogan forbade the testimony, citing the embarrassment it would cause to unnamed "individuals and entities" who were not directly involved in the case.

On Tuesday, however, Cogan allowed Cifuentes to testify about what he knew concerning bribes to Mexican presidents with only a few interruptions.

At one point, under questioning by Lichtman, Cifuentes acknowledged that his personal assistant, Andrea Velez Fernandez, had worked for a political consultant, J.J. Rendon, who was hired by Pena Nieto's presidential campaign. Cifuentes said Velez had once sent him photographs of "suitcases filled with cash".

When Lichtman asked if the suitcases were "destined for Mr Pena Nieto", prosecutors objected on the grounds of relevance.

"Agreed," Cogan said.

After that, there was no more discussion of the suitcases.