The 39-year-old Russian-born billionaire was stopped on Saturday at Le Bourget airport north of Paris, according to a statement from Paris prosecutor Laure Beccuau. The following day, a judge running the case extended his detention from 24 to up to 96 hours. 

Before that deadline lapses on Wednesday evening, the magistrate must decide whether to press charges against Durov or name him as a witness in the investigation and let him go free.

Durov is being interrogated as part of a case initiated by a cybercrime unit of the Paris prosecutor’s office.

Investigative judges handling the case are looking into a wide range of allegations. They include refusing to help authorities run legal wiretaps on suspects, enabling the sale of child sexual abuse material and aiding and abetting drug trafficking.

Earlier on Monday, an official at a French agency set up last year to prevent violence against minors wrote on LinkedIn that the case centered on “the lack of moderation and cooperation of the platform.”

In a statement released on its platform on Sunday, the Dubai-based company asserted that Durov has “nothing to hide” and that Telegram abides by European laws.

“It is absurd to claim that a platform or its owner are responsible for abuse of that platform,” the statement declared. “We’re awaiting a prompt resolution of this situation.”

Telegram was created by Durov and his brother Nikolai, a programmer and mathematician, and is one of the most popular messaging apps globally with 900 million active users. The company’s relatively hands-off approach to content moderation has led to allegations that it is commonly used for criminal activity and disseminating extremist material.

Prior to launching Telegram, the Durov brothers made their fortune in 2006 by founding the social media network VKontakte. The platform quickly became popular in Russia, and Pavel Durov now has a net worth of over $9 billion, according to the Bloomberg Billionaires Index.

This success also made Durov a Kremlin target. In 2014, he fled the country and sold his stake in VKontakte.

Durov, who lives in Dubai, is a citizen of France and the United Arab Emirates, according to Telegram’s website. He has not commented on whether he has renounced his Russian citizenship.

Following Durov’s detention, the Russian embassy in Paris said it “immediately asked the French authorities for an explanation of the reasons and demanded that they ensure the protection of his rights and provide consular access.” It added that embassy officials have been in touch with Durov’s lawyer.

French President Emmanuel Macron posted on X that Durov’s arrest was “in no way a political decision” and that it would be up to the judges to decide on the case.

“It’s the judicial system that will independently enforce the law,” Macron wrote.