Moscow Metro bombing: Why Chechens are suspected

Islamist radicals from the North Caucasus are nearly always at the top of the list of suspects when a bomb causes death and destruction in Russia.
All the more so, when the attack is carried out by female suicide bombers.
Guerrillas fighting to separate the republic of Chechnya from Russia adopted the suicide bombing tactic for the first time in 2000.

In 2002, women were members of the group that held a Moscow theatre audience hostage, until the building was gassed and stormed by security forces, with huge loss of life.
They were dressed in veils and bandanas that indicated their readiness to die in battle, and the following year came the first attacks by female suicide bombers.