Former presidents Enrique Pena Nieto, Felipe Calderon and Carlos Salinas de Gortari are among 17 Mexican politicians and a journalist named by Emilio Lozoya, the disgraced ex-head of state oil giant Petroleos Mexicanos, in his purported testimony to Mexican prosecutors, according to a leaked copy of his deposition seen by several media organizations.

While the Attorney General’s office wouldn’t confirm the authenticity of the document, stamped Aug. 11, it opened an investigation into how it was leaked to reporters on Wednesday, including by probing those who had access to the testimony. At least five of the 17 people mentioned in the document have turned to Twitter to reject the accusations.

Lozoya, who ran Pemex from late 2012 to early 2016 and was part of Pena Nieto’s inner circle, is cooperating with prosecutors after being extradited from Spain last month to face corruption charges. The case has become the widest-reaching graft probe in recent Mexican history and could build support for President Andres Manuel Lopez Obrador’s party, which is running on an anti-corruption platform, ahead of legislative and state elections next year.

The document cites Lozoya as saying Pena Nieto and his then finance minister Luis Videgaray ordered him to funnel bribes from Brazilian builder Odebrecht SA into the 2012 presidential campaign. Then, once in power, they told him to pay off lawmakers to help pass the country’s landmark energy reform in 2013 and 2014 and benefit favored companies.

Pena Nieto representatives did not immediately respond to a request for comment. Lozoya’s lawyer, Miguel Ontiveros, said in a statement posted on Twitter that the defense isn’t taking responsibility for the document and that the case should be kept in the courts to protect due process.

Lagging Behind

No former Mexican president in modern history has faced corruption charges or been sent to jail. Mexico has lagged behind other Latin American countries in mounting successful cases, previously failing to prosecute bribery allegations that surfaced out of a Brazilian probe of Odebrecht and landed top officials around the region, including presidents, in jail.

Lozoya’s purported testimony also alleged that his predecessor, Felipe Calderon, had benefited Odebrecht while Carlos Salinas, who ruled Mexico from 1988-1994, had allegedly helped companies win contracts.

Calderon accused Lopez Obrador of using Lozoya as an instrument of “vengeance and political persecution.”

“He’s not interested in justice but in a lynching, in my case making ridiculous accusations,” Calderon said of the president in his Twitter account on Wednesday night.

The document did not include proofs of Lozoya’s claims and lawyers have warned the publicity around the case, including comments by Lopez Obrador during his daily press conference, could be undermining the right to a fair trial. Lopez Obrador has been demanding that an alleged video and other evidence in the case be made public.

Jose Antonio Meade, who was named in the document and served as foreign minister at the time of the allegations and later ran for the presidency under the banner of Pena Nieto’s party, said in a post in Twitter that Lozoya’s condition as a protected witness should “serve to know the truth, not to accuse without proof those who denounced crimes and helped bring this case to justice.”

“I dedicated my life to build a better country with absolute honor and legality,” Meade said.