Summarise the following text using different wording than in the original: A well-known Russian military blogger was killed in an explosion at a cafe in St. Petersburg on Sunday, officials said, in what appeared to be an audacious attack on a high-profile pro-Kremlin figure. Vladlen Tatarsky died when a blast tore through the cafe where he was appearing as a guest of a pro-war group called Cyber Front Z. Authorities said they were treating the case as suspected murder. Twenty-five other people were injured in the blast, 19 of whom were hospitalized, the city’s governor said. The Russian Ministry of Health said six people were in critical condition. Investigators were questioning everyone who was inside the cafe, state media reported. Photos of the scene showed extensive damage to the building in which the cafe was located.