The lawsuit filed by Spain’s state legal services argues the judge and others may have committed “criminal acts” in his summons by not allowing Sánchez to testify in writing as requested by the Socialist leader, according to the complaint.

The lawsuit “is not a frontal attack on the judiciary”, the document said.

“On the contrary, it is an expression of confidence in the judiciary, which alone is capable of putting an end to an abuse, in this case a judicial abuse attributable to one of the more than 5,000 judges who exercise their functions in Spain.”

Sánchez on Tuesday opted not to answer questions from judge Juan Carlos Peinado, who is heading the preliminary inquiry into his wife Begoña Gómez’s business ties, at the premier’s official residence.

Under Spanish law, one can refuse to answer questions in a case affecting close family members, including spouses.

Sánchez asked to testify in writing, as allowed under Spanish law for top government officials, but Peinado rejected the request, arguing he would quiz him in his role as Gómez’s spouse.

“You cannot separate one person into two and claim that you are going to question him as his spouse, when what determines the subject of the investigation…is the fact that the husband of the person under investigation is the head of government,” the lawsuit stated.

Gómez, who has worked in fundraising for years, is being investigated for alleged influence-peddling and corruption following a complaint filed by anti-graft NGO “Manos Limpias” — Spanish for “Clean Hands” — which has links to the far right.

She is alleged to have used her husband’s position as leverage within her professional circles, notably with businessman Juan Carlos Barrabés, who was seeking public funding.

She has not spoken publicly about the case but Sánchez has denied any wrongdoing by his wife and dismissed the allegations as part of a right-wing smear campaign against his left-wing government.