The Mexican General Prosecutor’s Office (FGR) announced on Friday that legal proceedings had been initiated against former Secretary of the Economy Ildefonso Guajardo, launching a criminal investigation into allegations of illicit enrichment.

Guajardo, who is due to re-enter Congress as a member of the opposition Institutional Revolutionary Party in September, is alleged to have “probably obtained an unjustified increase in his assets” by virtue of his position as a senior official in the previous administration. Guajardo has dismissed these accusations as “baseless and unfair,” and an example of political persecution.

In Friday’s press release, the FGR said that a judge had decided to impose precautionary measures on Guajardo for the duration of the proceedings, including a prohibition on leaving the country without judicial authorization, and a requirement that he report to authorities periodically.

According to Guajardo, the FGR had also lodged an application to suspend his swearing-in ceremony as a Federal Congressman, but that this had been rejected by the judge.

In a statement shared on Twitter, Guajardo said:

I remain confident and at peace, knowing that honesty and decency have always been a critical part of me throughout my years of experience as a public official. . . Honor and prestige are not built in a day, and, through 40 years in public service I have given ample proof that I am an honest man, by virtue of my work and my results.

The FGR has been granted four months to investigate the allegations.