A Spanish investigative judge has summoned the wife of Spain’s prime minister to give testimony as part of a probe into allegations that she used her position to influence business deals, a Madrid-based court said Tuesday.

Begoña Gómez is to appear at court on July 5 to answer questions.

Gómez has yet to speak publicly on the case, but Prime Minister Pedro Sánchez has called it a “smear campaign” to damage Spain’s leftist coalition government led by his Socialist party.

The probe is based on allegations against Gómez made by a group called Manos Limpias, or “Clean Hands.” Manos Limpias describes itself as a union, but its main activity is as a platform pursuing legal cases. Many have been linked to right-wing causes targeting leftist politicians, and most of them never succeed.

After the probe was launched in April, Sánchez stunned the nation by saying he would contemplate stepping down for what he said was the “attack without precedent” against his wife. After five days of silence, Sánchez said he had decided to remain in office.

The summoning of Gómez comes before this week’s European Parliament election, with Spaniards voting on Sunday. Far-right parties across Europe aim for big gains.

“I want to express our surprise for the fact and coincidence that this news is coming out precisely this week,” said Pilar Alegría, spokeswoman for Spain’s government.

“We are absolutely calm because we know there is nothing (to the allegations),” Alegría said. “What does exist is a mudslinging campaign by the right and far right.”

Manos Limpias has said its allegations against Gómez were entirely based on media reports: “If they are not true, it would be up to those who published them to admit to their falsehood, but if they are true, then we believe that the legal case should continue forward.”

Spain’s public prosecutors’ office recommended the probe be thrown out, but a provincial court ruled that the lower-court judge could continue the investigation. The judge will either table the probe or recommend it go to trial.