Peru’s attorney general has opened a new probe of President Pedro Castillo, a day after the country’s former interior minister accused the leftist leader of obstructing graft investigations of close allies, prosecutors said on Thursday.

Mariano Gonzalez, who had been the interior minister for two weeks, was abruptly fired by Castillo on Tuesday. This action set off the probe. Gonzalez was dismissed after he gave the go-ahead for the creation of a special police unit to find and apprehend presidential sympathizers who are the subject of criminal investigations.

Peru’s prosecutors office said on Twitter that the investigation initiated by Attorney General Patricia Benavides was for alleged concealment and was linked to the former interior minister’s firing. The office provided no more details.

Presidents in Peru have immunity and cannot be indicted by the courts during their five-year term, but they can be investigated.

Castillo, who has been in office for just under a year, is in an increasingly precarious position, with low approval ratings and scandals brewing in his inner circle. He has already survived two impeachment attempts, and some lawmakers are calling for a third political trial over the new allegations.

Presidential allies under investigation include a former transportation minister, a former presidential adviser, a nephew and Castillo’s sister-in-law.

In May, the attorney general opened a separate investigation of Castillo over alleged influence peddling, collusion and being part of a “criminal organization.”