X owner Elon Musk was summoned Monday to Paris where investigators are looking into allegations of misconduct related to the social media platform including the spread of child sexual abuse material and deepfake content.

Musk, the world’s richest man, has been summoned along with former X CEO Linda Yaccarino for “voluntary interviews,” while other employees of the platform, formerly known as Twitter, are set to testify this week, the Paris prosecutor’s office said.

Whether Musk and Yaccarino will travel to Paris to voluntarily testify is unclear, according to the Associated Press. Neither responded to the wire service’s request for comment. 

However, Musk has welcomed a report that U.S. justice officials have declined to help French investigators, the Associated Press also reports.