A woman accused of being involved in the bombing that killed Russian military blogger Vladlen Tatarsky is set to face a court hearing.
Darya Trepova, 26, was arrested by police after Mr Tatarsky was killed on Sunday at a St Petersburg cafe as he led a discussion.
Mr Tatarsky, 40, was an avid supporter of the war in Ukraine who filed daily reports on the fighting from the front lines.
Ms Trepova is set to face a court hearing in Moscow on Tuesday that will set terms for her pre-trial detention.
She was seen on video moments before the blast presenting Mr Tatarsky with a statuette that is believed to have contained explosives.
Russian authorities described the bombing as an act of terrorism and blamed Ukrainian intelligence agencies for orchestrating the attack.
The Interior Ministry released a video in which Ms Trepova told a police officer that she brought the bust to the cafe.
When asked who gave it to her, she said she would explain later. The circumstances under which Ms Trepova spoke were unclear, including whether she was under duress.
The National Anti-Terrorist Committee, which coordinates counterterrorism operations, said the bombing was “planned by Ukrainian special services,” noting Ms Trepova was an “active supporter” of imprisoned Russian opposition leader Alexei Navalny.
Last year she was arrested and spent 10 days in custody after taking part in an anti-war rally.
Ukrainian authorities did not directly respond to the accusation, but President Volodymyr Zelensky said in reference to the attack that he doesn’t think about events in Russia, and his top adviser described the bombing as part of Russia’s internal turmoil.
While Ms Trepova was arrested in St Petersburg, her case was sent to Moscow, where the headquarters of the country’s top investigative agencies are located, in an apparent reflection of its high priority.
She will face a hearing at Moscow’s Basmanny District Court that is expected to order her to be held in custody pending the investigation.
Russian law envisions a life sentence for terrorist crimes.
The bombing, which injured 40 other people, 25 of whom have been hospitalised, was the latest attack inside Russia on a high-profile pro-war figure.
Last year, a nationalist TV commentator was assassinated when a bomb exploded in her SUV outside Moscow.
Mr Tatarsky was the pen name of Maxim Fomin, who had accumulated more than 560,000 followers on his Telegram messaging app channel.
Mr Tatarsky, who joined separatists in eastern Ukraine after a Moscow-backed insurgency erupted there in 2014, fought on the front lines for years before turning to blogging.
Military bloggers have become increasingly visible, supporting the war but occasionally exposing flaws in Russian military strategy while the Kremlin has shut independent media outlets and muzzled any criticism of the war.
