Telegram founder Pavel Durov was released from police custody in France on Wednesday, August 28 and transferred to court for questioning ahead of a possible indictment, French prosecutors have revealed, days after the Russian-born billionaire was arrested at a Paris airport.

Durov left the anti-fraud office outside Paris in what appeared to be a police vehicle on Wednesday afternoon according to reports and the Paris prosecutor’s office said he would now face “initial questioning and possible indictment” at a court in the French capital.

Durov, 39, was detained at Paris’s Bourget Airport on Saturday on a warrant related to Telegram’s lack of moderation. He was being investigated on charges relating to a host of crimes, including allegations that his platform was complicit in aiding fraudsters, drug traffickers and people spreading child pornography.

Durov’s app, and its lack of content moderation, has also come under scrutiny for its use by terrorist groups and far-right extremists.

He was placed in custody for up to 96 hours, the maximum amount of time someone can be held under French law before being charged.

Durov’s arrest started a row over freedom of speech and caused particular concerns in both Ukraine and Russia, where Telegram is extremely popular and has become a key communication tool among military personnel and citizens during Moscow’s war on its neighbour.

French President Emmanuel Macron on Monday said the decision to bring charges against Durov was “in no way political,” a rare intervention by a French leader into a judicial matter.

Telegram was launched in 2013 by Durov and his brother, Nikolai. The app now has more than 950 million users, according to a post from Durov last month, making it one of the most widely used messaging platforms in the world.

Conversations on the app are encrypted, meaning that law enforcement agencies and Telegram itself can't see what users post.