Russian researchers a woman was arrested on Monday hunting for the killers of pro-war blogger Vladlen Tatarsky in a St. Petersburg cafe explosion.

Daria Trepova, 26, was on the Ministry of the Interior’s wanted list. His arrest was later confirmed by the Russian Investigative Committee.

Russian media reported that Tatarsky was handed a statuette shortly before the explosion and there is speculation that there may be a hidden device inside.

More than 30 people were injured in the blast.

A carefully planned attack

Authorities said the attack downtown the second largest city of Russia was being treated as a “high profile murder” and what it was carefully planned and it involved several people.

Trepova was detained in a St. Petersburg apartment owned by a friend of her husband’s, according to Russian reports.

On the day of last year’s large-scale invasion of Russia, she was reportedly detained for several days for participating at an anti-war protest.

Tatarsky had attended a patriotic rally with supporters in the cafe as a guest speaker.

A video circulating on social media shows a young woman in a brown coat appearing to enter the café with a cardboard box.