[HIGHLIGHTS] National condolences! Russia suffered a "bloody terrorist attack". Who was behind the careful planning?

On March 22, local time, a shooting occurred at a concert hall in Krasnogorsk, a suburb of the Russian capital Moscow. 11 people have been detained, including 4 direct participants in the Moscow terrorist attack.

"Elaborate planning" started a month ago. Putin declared March 24 as a national day of mourning. Russia suffered a "bloody terrorist attack". Who was behind the careful planning?.. 　　China News Service, March 24 (Zhang Aolin He Luman)