Darya Trepova believed she was on a “propaganda resistance” test for a job at a Kyiv-based website when she handed Vladlen Tatarsky the bomb that killed him, Fontanka, a St Petersburg news site, reported.
It cited leaked transcripts of her interrogation by Russia’s FSB security service.
Russian prosecutors on Tuesday charged Ms. Trepova with terrorism, two days after Tatarsky, 40, was killed in the blast.
The investigative committee, which probes major crimes, said it had charged Ms. Trepova with committing “a terrorist act by an organized group that caused intentional death”. It carries a maximum jail term of 20 years.
The committee said Ms. Trepova had acted under instructions from people working on behalf of Ukraine.
Fontanka claimed Ms. Trepova “was offered a job on a news website in Kyiv” but first had to prove “she knew how to resist Russian propaganda”.
During her arrest on Monday, the 26-year-old admitted that she had carried the bomb into the cafe. Her husband said that she was framed.
The bomb was hidden in a golden bust of Tatarsky. He was the only person killed when it exploded at a talk he was giving at the venue while more than 40 people were injured.
The Kremlin and the FSB have accused Ukrainian secret services of organizing the attack. They leaked dozens of videos and photos proving Ms Trepova’s guilt.
Ms Trepova is known to be a supporter of Alexander Navalny. 46, the imprisoned Russian opposition leader, also to oppose Mr Putin’s war in Ukraine. However, she has said that she was an unwitting bomb mule in Tatarsky’s assassination.
According to Fontanka, Ms Trepova had met him at a talk a few days earlier. She was then told to collect a package from a contact and hand it to Tatarsky on Sunday.
An FSB officer asked Ms Trepova if she was suspicious of the package. “I wasn’t specifically told what was in it but I suspected something bad,” she said.
A video of the moment before the bomb exploded at the Street Bar appeared to show Tatarsky and Ms Trapova on familiar terms. After she hands him the bomb, he asks her to sit to one side, closer to him.
She does not appear alarmed or give the impression that she has just handed over a bomb to a murder target.
Another video, filmed outside immediately after the bomb blast, shows Ms Trepova strolling, as if in a daze, out of the smashed cafe. She appears uninjured and walks away.
This is the second high-profile assassination of a Kremlin propagandist in the past eight months. Ukraine was blamed for killing pro-war journalist Darya Dugina, 29, with a car bomb in August but Kyiv denied that it had killed Tatarsky.
