Little is known about the inner workings of the Kremlin, especially with Vladimir Putin in power.

This week on Conflict Zone: former Russian Prime Minister Mikhail Kasyanov, who served in Putin's first administration from 2000-2004. He knows what happens behind the closed doors of the Russian government.

He says he feared for his own life after opposition politician Boris Nemtsov was killed in 2015. And still does.

Mikhail Kasyanov: “Everyone in Russia should be scared.”