A lot more details here, including more aftermath footage, and the deeply unsurprising news that the bomber was a “man of Arab appearance.”
Also this:
Three men who have been living in the Russian capital for a certain period of time reportedly took part in organizing the blast, a source told Interfax news agency. He also noted that these three were believed to be Russian North Caucasus militants.
The North Caucasus area is where Chechnya is located, where Russia is still occupying Georgian territory, where a dizzying array of post-Soviet Russian Republics (Adygea, Karachay-Cherkessia, Kabardino-Balkaria, North Ossetia, Ingushetia, Dagestan) of differing ethnicities reside, and where jihadists have declared a Caucasus Emirate, claiming most of the land between the Caspian and the Black Sea.
However, having news of North Caucasus involvement available so soon after the bombing seems quite strange. It could very well be Jihadest involvement, or it could be Vladamir Putin manufacturing a pretext for cracking down on the regions various separatist movements.
(Hat tip: PowerLine.)