Pavel Durov, the founder and CEO of the messaging app Telegram, was arrested in Paris over the weekend over allegations that his platform is being used for illicit activity such as drug trafficking and the distribution of child sexual abuse images.

Durov, who was born in Russia, spent much of his childhood in Italy and is a citizen of France, Russia, the Caribbean island nation of St. Kitts and Nevis and the United Arab Emirates. He was taken into custody at Paris-Le Bourget Airport in France on Saturday after landing from Azerbaijan.

In a statement posted to its platform, Telegram said it abides by EU laws and its content moderation is “within industry standards and constantly improving.” Durov, the company added, “has nothing to hide and travels frequently in Europe.”

Here are some details on Telegram, the app at the center of Durov’s arrest.

What is Telegram?

Telegram is an app that allows for one-on-one conversations, group chats and large “channels” that let people broadcast messages to subscribers. Unlike rivals such as Meta’s WhatsApp, Telegram’s group chats allow as many as 200,000 people, compared to a maximum of 1,024 for WhatsApp. Experts have raised concerns that misinformation spreads easily in group chats of this size.

Telegram offers encryption for their communications, but — contrary to a popular misconception — this feature is not on by default. Users have to switch on the option to encrypt their chats. It also doesn’t work with group chats. That contrasts with rival Signal and Facebook Messenger, where chats are encrypted end-to-end by default.

Telegram says it has more than 950 million active users. It is widely used in France as a messaging tool, including by some officials in the presidential palace and in the ministry behind the investigation into Durov. But French investigators have also found the app has been used by Islamic extremists and drug traffickers.

Telegram was launched in 2013 by Durov and his brother Nikolai. According to Telegram, Pavel Durov supports the app “financially and ideologically while Nikolai’s input is technological.”

Before Telegram, Durov founded VKontakte, Russia’s largest social network. The company came under pressure amid the Russian government’s crackdown after mass pro-democracy protests rocked Moscow at the end of 2011 and 2012. Durov said government authorities demanded that the VKontakte take down the online communities of Russian opposition activists. It later asked the platform to hand over the personal data of users who took part in the 2013 uprising in Ukraine, which eventually ousted a pro-Kremlin president.

But Durov sold his stake in VKontakte after pressure from Russian authorities in 2014. He also left the country. Today, Telegram is based in Dubai, which Durov called “the best place for a neutral platform like ours to be in if we want to make sure we can defend our users’ privacy and freedom of speech” in an April interview with conservative talk show host Tucker Carlson.

Why was Durov arrested?

French media has reported that Durov was detained on an arrest warrant alleging his platform has been used for money laundering, drug trafficking and other offenses. As of Monday afternoon, he had not been charged, and few details were available on the investigation.

On Sunday night, a French investigative judge extended Durov’s detention order, French media reported on Monday. Under French law, Durov can remain in custody for questioning for up to four days. After that, judges must decide to either charge him or release him.

What has been the response?

In Russia, Kremlin spokesman Dmitry Peskov declined to comment on reports of Durov’s arrest in France.

“We still don’t know what exactly Durov is being accused of,” Peskov said Monday during his daily media conference call. “We haven’t heard any official statements on that matter.”

“Let’s wait until the charges are announced – if they are announced,” Peskov said.

Russian government officials have expressed outrage at Durov’s detention, with some calling it politically motivated and proof of the West’s double standard on freedom of speech. The outcry has raised eyebrows among Kremlin critics: in 2018 Russian authorities themselves tried to block Telegram but failed, withdrawing the ban in 2020.

Elsewhere, Elon Musk, the billionaire owner of X who has called himself a “ free speech absolutist,” has been speaking out in support of Durov and posted ”#freePavel” following the arrest.

In a statement posted on its platform after his arrest, Telegram said it abides by EU laws, and its moderation is “within industry standards and constantly improving.”

“It is absurd to claim that a platform or its owner are responsible for abuse of that platform,” Telegram’s post said. “Almost a billion users globally use Telegram as a means of communication and as a source of vital information. We’re awaiting a prompt resolution of this situation. Telegram is with you all.”

Does Telegram moderate content?

Western governments have often criticized Telegram for a lack of content moderation, which experts say opens up the messaging platform for potential use in money laundering, drug trafficking and the sharing of material linked to the sexual exploitation of minors.

Compared to other messaging platforms, Telegram is “less secure (and) more lax in terms of policy and detection of illegal content,” said David Thiel, a Stanford University researcher, who has investigated the use of online platforms for child exploitation, at its Internet Observatory.

In addition, Telegram “appears basically unresponsive to law enforcement,” Thiel said, adding that messaging service WhatsApp “submitted over 1.3 million CyberTipline reports in 2023 (and) Telegram submits none.”

In 2022, Germany issued fines of 5.125 million euros ($5 million) against the operators of Telegram for failing to comply with German law. The Federal Office of Justice said that Telegram FZ-LLC hasn’t established a lawful way for reporting illegal content or named an entity in Germany to receive official communication.

Both are required under German laws that regulate large online platforms.

Last year, Brazil temporarily suspended Telegram over its failure to surrender data on neo-Nazi activity related to a police inquiry into school shootings in November.

Telegram said in response to the arrest that it abides by EU laws and its content moderation is “within industry standards and constantly improving.”