Pavel Durov, the billionaire CEO and founder of messaging app Telegram who was arrested in France on Saturday, is also a suspect in a criminal case in Switzerland, Forbes has learned. The case was filed by his former partner Irina Bolgar, who claims to have three children with Durov. The criminal complaint in Geneva, filed in March 2023, alleges that Durov was physically violent towards one of his three children. Bolgar filed a civil child custody case shortly after; both cases were submitted a few months after Bolgar alleges Durov stopped paying her 150,000 euros ($167,500) per month in child support, court filings say.

The Geneva Court of Justice initially refused to enter the criminal complaint against Durov when it received it because it had been filed more than three months after the most recent instance of alleged physical violence. In May 2023, Bolgar appealed, and the court allowed the case to move forward last October. The case—which is ongoing, according to a Geneva court official—alleges that Durov harmed his youngest son, born in September 2017, five times between 2021 and 2022. The incidents allegedly resulted in injuries including a concussion and sleep disorders; transcripts of messages purportedly exchanged by Bolgar and Durov in November 2021 in Paris were entered as evidence, as was a medical certificate from April 2023 attesting that the child continued to suffer from anxiety and had trouble sleeping due to the violence.

A representative for Durov declined to comment. A lawyer for Bolgar confirmed that Bolgar and her three children are involved in the civil case but declined to comment on the criminal complaint. Because of Swiss laws, Durov, Bolgar and their children are not named in the criminal case, but there are several identifying details that confirm Durov’s identity including his children’s birth years, the case number of the civil child custody case, Durov’s residence in the United Arab Emirates and a reference to his net worth. Durov did not contest the child custody case, which was decided in Bolgar’s favor in May 2023 and reaffirmed in February 2024, according to Bolgar’s lawyer. It’s unclear if he has hired an attorney in the criminal complaint. Bolgar’s lawyer told Forbes she also filed a civil child support case against Durov in June 2024, which remains ongoing.

Bolgar met the Telegram founder in 2012, when they were both living in Russia, she wrote on social media. Six months later they moved to St. Petersburg, where their three children were born between 2013 and 2017. According to her Instagram, she and Durov lived together in St. Petersburg until 2017. Durov founded Telegram in 2013 and claimed that he left Russia in 2014 after refusing to provide data on users of his social media site VKontakte to Russian officials. But, according to Russian investigative news outlet iStories, he returned more than 50 times between 2015 and 2021.

Durov later gained French citizenship and moved to Dubai in 2017. He is also a citizen of the United Arab Emirates and St. Kitts and Nevis. Worth an estimated $15.5 billion, Durov lives in a luxury five-bedroom villa on a 15,000-square-foot property in Dubai’s Jumeirah Islands, which he rents for about $1 million a year.

Bolgar and Durov never married; because children born outside of marriage were not legally recognized in the UAE at the time, Bolgar and their three children stayed in Russia, according to one of Bolgar’s Instagram posts. According to the criminal case, Durov and Bolgar separated at the end of 2018 and Durov committed in writing that he would pay Bolgar monthly child support of 150,000 euros. In 2019, Bolgar and the children moved to Latvia before leaving for Switzerland in 2020. She and her children continued to see Durov in the years after their separation, meeting in Switzerland, Dubai and in other countries, according to an Instagram post.

In court filings, Bolgar alleges that Durov stopped seeing their children in September 2022 and then “blocked” access to the 150,000-euro child support payments around the same time. According to the complaint, Bolgar, who is a lawyer according to her social media, has relied on her 8,000 Swiss franc ($9,500) monthly salary to support the children since then. She filed a case seeking sole custody over the children with a civil court in Geneva in April 2023. The court granted Bolgar exclusive custody over her children with Durov and suspended his personal rights with the children, first in May 2023 and again in February 2024. He appears to have never responded to the court or hired a lawyer.

Forbes Russia verified the authenticity of the children’s paternity documents with the Geneva-based translator used by Bolgar when she moved to Switzerland. Forbes also viewed photocopies of the documents and their translations, which state Durov’s full name and date of birth, including his middle name and place of birth.

While Durov has yet to acknowledge these three children, he posted on Telegram in July that he has more than 100 biological children from donating his sperm. He also reportedly has two older children from a previous relationship. One day after Durov’s Telegram post, Bolgar began to post publicly on Instagram about her children and relationship with Durov.

The Switzerland case is ongoing as Durov remains in police custody in France, where he was arrested at Le Bourget airport outside Paris on Saturday evening after arriving in a private jet from Baku, Azerbaijan. In a statement shared with Forbes, Laure Beccuau, the Paris prosecutor in charge of the case, stated that Durov had been taken into custody as part of a judicial investigation opened on July 8, 2024, by JUNALCO, France’s national anti-organized crime and cybercrime unit. He is being investigated for 12 counts including complicity in administering an online platform to enable illicit transactions, distribution of child pornography, selling narcotics, fraud and money laundering. On Sunday, his custody was extended by up to 96 hours, meaning he can be held until Wednesday, August 28, before being charged or released.

The child pornography allegations involving Telegram appear to be central to the investigation. “At the heart of this case is the lack of moderation and cooperation of [Telegram] (which has nearly 1 billion users), particularly in the fight against pedocriminality,” wrote Jean-Michel Bernigaud, general secretary of OFMIN, the French agency focused on preventing violence against minors, in a LinkedIn post on Monday.

In a statement published on Sunday, Telegram said that the firm “abides by EU laws” and that Durov “has nothing to hide and travels frequently in Europe,” adding that the company is “awaiting a prompt resolution of this situation.”