Pavel Durov, the cofounder and CEO of messaging app Telegram, was arrested in France on Saturday evening, according to French media.
Sources told the TV network TF1 that he was arrested at the Bourget airport outside Paris after traveling in his private jet from Azerbaijan.
The report added that a warrant had been issued as part of a police investigation into a lack of moderators on Telegram, which allowed criminal activity to allegedly take place.
Telegram did not immediately respond to a request for comment from Fortune.
Durov was born in Russia and lives in Dubai, where Telegram is based, carrying dual citizenship in France and the United Arab Emirates.
He and his brother, Nikolai, founded Telegram in 2013 but left Russia in 2014 after Pavel refused to provide encrypted user data to Russia’s secret service and to shut down opposition communities on a separate social network that he later sold.
He moved to Dubai in 2017 and became a French citizen in 2021, according to Forbes, which puts Durov’s net worth at an estimated $15.5 billion.
Telegram, which has about 900 million active users, has grown in popularity as a way to more securely communicate via its encrypted messages.
While it has been used in conflict zones, as well as by militant groups, Durov has said Telegram is a neutral platform and not a “player in geopolitics.”
