French police arrested Telegram CEO and founder Pavel Durov on Saturday at an airport near Paris for alleged offences related to the popular messaging app, French media reported.

The French-Russian billionaire, 39, was detained at Le Bourget airport north of the French capital on Saturday evening, one of the officials told AFP, speaking on condition of anonymity.

French television news outlets TF1 TV and BFM TV also reported the arrest, citing unnamed sources, according to Reuters.

He had just travelled from Baku, in Azerbaijan, another source close to the case told AFP.

Durov was expected to appear in court on Sunday.

Telegram did not immediately respond to a request from Reuters for comment, and the French Interior Ministry and French police had no comment either.

France’s OFMIN, an agency tasked with preventing violence against minors, had issued an arrest warrant for Durov as the coordinating agency in a preliminary investigation into alleged offences including fraud, drug trafficking, cyberbullying, organized crime and promotion of terrorism, one of the sources close to the case told AFP.

Durov is suspected of failing to take action to curb the criminal use of his platform.

“Enough of Telegram’s impunity,” said one of the investigators, adding they were surprised Durov came to Paris knowing he was a wanted man.

Durov started Telegram in 2013 and left Russia in 2014 after he was ousted from VKontakte — a popular social networking site in Russia which he-cofounded — after being pressured by the Kremlin to hand over users’ personal data, which he refused to do.

In a 2016 interview with “60 Minutes,” Durov said he was “horrified” when he learned that Telegram — which was designed to be heavily encrypted so that governments cannot access users’ personal data — was being used by terrorist groups like the Islamic State to communicate.

“I’m personally for the privacy side,” Durov said in that interview when asked whether privacy concerns outweighed security risks. “But one thing that should be clear is that you cannot make just one exception for law enforcement without endangering private communications of hundreds of millions of people because encryption is either secure or not.”