A summons addressed to “suspect Durov P.V.” arrived by mail at Telegram founder Pavel Durov’s former apartment in Russia, Durov said.

Writing on his Telegram channel on the evening of April 22, Durov said the notice had been delivered to an apartment in Russia where he had lived 20 years ago. He joked that he was probably suspected of upholding Articles 29 and 23 of the Russian Constitution, which guarantee freedom of speech and the right to privacy of correspondence, and declared himself proud of his guilt.

It remains unclear who sent the notice. The image Durov published on his Telegram channel appears to show a Russian Post notification form for a registered letter. It is also unclear why the document identifies the recipient as “suspect” rather than simply listing a surname and initials.

Pavel Khlyustov, a lawyer, told the Russian business news outlet RBC that the image shows a postal notification for a registered letter, not a summons. He called it “extremely strange” that the status of “suspect” had been indicated on the envelope itself, noting that investigators do not normally do this — though the law does not explicitly prohibit it.

The independent Russian news outlet Mediazona suggested that the letter addressed to “suspect Durov” may have been sent from the territory of the self-proclaimed Donetsk People’s Republic, based on the tracking code digits — 2830. The prefix 283 is assigned to the self-proclaimed Donetsk People’s Republic, and post offices whose codes begin with 2830 are located in Donetsk.

Durov announced in February that Russian authorities had opened a criminal case against him on charges of facilitating terrorist activity. He called it “a sad spectacle of a state afraid of its own people.”

Rossiyskaya Gazeta, the Russian government’s official newspaper, and the pro-Kremlin tabloid Komsomolskaya Pravda were the first to report the criminal investigation into Durov. Law enforcement agencies made no official announcement.