Eye of the Red Tsar by Sam Eastland

Pekkala was once the most trusted secret agent of Tsar Nicholas Romanov. But now, a decade after the execution of the Tsar and his family, Pekkala is Prisoner 4745-P in a desolate Siberian prison camp. He is released from prison and given a mission he can't resist: find out who really killed the Romanovs and locate the rumored survivor of the assassination. This is a great thriller!