Prosecutors have raided the French headquarters of Elon Musk’s social media platform X and summoned the tech billionaire and the company’s former chief executive for questioning as part of an investigation into alleged cybercrime.

“A search is under way by the cybercrime unit of the Paris prosecutor’s office, the national police cyber unit and Europol,” the Paris prosecutors’ office said in a post on X on Tuesday, adding that it would no longer be publishing on the network.

It said in a statement that Musk and Linda Yaccarino had been summoned for “voluntary questioning” in their capacity as “de facto and de jure managers of the X platform at the time of the events”. Yaccarino resigned as chief executive of X in July last year.

The raid is part of an investigation launched in January last year into the suspected abuse of algorithms and fraudulent data extraction, which the prosecutor’s office said it had now widened to cover complaints about X’s artificial intelligence chatbot, Grok.

It said the alleged offences it was investigating now included complicity in the possession and organised distribution of child abuse images, violation of image rights through sexualised deepfakes, and denial of crimes against humanity.

Other possible charges included fraudulent data extraction from, and falsified operation of, an automated data processing system by an organised group, and operation of an illegal online platform by an organised group, the statement said.

French authorities launched the investigation after the centre-right MP Éric Bothorel filed a complaint alleging that biased algorithms on the platform were likely to have distorted its data processing system and affected the kind of content it recommended.

Bothorel complained of a “reduced diversity of voices” and Musk’s “personal interventions” in X’s management since he bought it in 2022. Another complaint said the changes had led to a surge in “nauseating political content”.

Prosecutors said in November that they were expanding the investigation to include the behaviour of Grok, which allegedly engaged in Holocaust denial, advancing false claims commonly made by people who deny Nazi Germany murdered 6 million Jews.

The chatbot has since caused outrage by allowing users to “strip” clothed people, including children, in photos through AI image generation and editing. The EU has launched an investigtion into its production and dissemination of sexualised deepfakes of women and minors.

X has been approached for comment on Tuesday’s raid. The company said last summer it did not intend to comply with French prosecutors’ demands, which it described as “politically motivated”, and denied all allegations against it.

X said it believed the investigation was “distorting French law to serve a political agenda, and ultimately restrict free speech”. It said it was committed to “defending its fundamental rights, protecting user data and resisting political censorship”.

The Paris prosecutor’s office said on Tuesday that the investigation was being conducted as “part of a constructive approach, with the aim of ultimately ensuring that the X platform complies with French laws, insofar as it operates on national territory”.

Despite being described as voluntary, the summonses issued to Musk and Yaccarino are mandatory, but they are hard to enforce on people outside France. Afterwards, authorities can potentially place suspects in custody.

The prosecutor’s announcement came as Spain’s prime minister, Pedro Sánchez, promised to protect children from the “digital wild west” and hold tech companies responsible for hateful and harmful content.

As his government prepares a series of measures including a ban on under-16s having social media accounts, Sánchez said on Tuesday that urgent action was needed because social media was a “failed state where laws are ignored and crimes are tolerated”.

The measures would oblige platforms to bring in age-verification systems and ensure executives were held legally accountable if content that violates the law or is considered hate speech is not removed.

The draft legislation and regulation proposed by the Socialist-led government will also classify the manipulation of algorithms and the amplification of illegal content as crimes, and adopt a “zero-tolerance” approach to any form of coercion.