A Russian anti-war activist dies in custody after claiming to have been tortured.

A Russian activist has died in prison days after he described being tortured and fearing for his life, his lawyer said.

Anatoly Berezikov, 40, died about a month after being detained by police at his home in the southern city of Rostov-on-Don and was charged with misconduct, which he denied. His lawyer, Irina Gak, said he was known to have put up posters in the city to promote the anti-war initiative “I Want to Live” which helps Russian military in Ukraine to surrender, and that it made him a target had made.

Rostov region police told local news media that Mr Berezikov was found in his cell on Wednesday with no signs of life, a report that attempted to paint his death as a suicide. Police declined to provide additional details when contacted by The New York Times, and no other official has commented on Mr Berezikov’s death.

Mr Berezikov is believed to be the first person in Russia to die in police custody after being jailed for resisting the invasion of Ukraine. Tens of thousands of Russians have been held under draconian laws criminalizing criticism of the war since the invasion began, but most were released soon after.

Of the roughly 600 Russians charged with crimes related to opposition to the war, 37 have described being tortured, according to Dasha Korolenko, a lawyer for the country’s human rights organization, OVD-Info, who has information on each case collects.

Mrs. Gak, the lawyer, said that a day before his death Mr. Berezikov had told her that he had broken ribs and had marks on his body that he said were from an anaesthetic.

“He said he was threatened, that he feared for his life,” Ms Gak said in a video posted on social media by OVD-Info on Thursday. Ms. Gak did not immediately respond to requests for an interview.

Another local opposition activist, Tatyana Sporysheva, said she spoke Mr Berezikov in court just days before his death and described him with threats and intimidation. She said that Mr. Berezikov told her, “I’m afraid they will kill me.”

Ms. Sporysheva described Mr. Berezikov as a well-known member of his community who did things like ride a bike in shorts and a Santa hat in freezing winter weather to cheer up fellow residents.

Rostov-on-Don is located near the Sea of ​​Azov and is an important military logistics hub for the Russian war effort.

After his detention, Mr. Berezikov was charged with several minor offenses, including hooliganism, which allowed the authorities to keep him in custody. His final 15-day sentence was due to end on Thursday, but Ms Sporysheva said he had predicted at his sentencing that he wouldn’t survive that long, telling her: “I won’t make it to June 15.”

Alina Lobzina reporting contributed.