Quote Originally Posted by Tukhachevskii View Post
Perpetrators also enacted deception and security measures (apparently) by impersonating police/militsia officers.
They frequently do this. One particularly ugly example was during the 2004 raid on Nazran in Ingushetia which killed around 100 law enforcement officers (they mostly spared the traffic police). They set up a roadblock dressed as local law enforcement and checked motorists documents; any responding law enforcement officers were executed.

Local police in Dagestan are thoroughly penetrated by the rebels, and corruption is rife. The bomber may well have even been an actual policeman.