sentence1: Kotkin describes how Lev Kamenev, Stalin's old Pravda co-editor, and Grigory Zinoviev, who with Stalin and Kamenev had formed a ruling troika during Lenin's final illness, were dragged out of their prison cells in 1936 for a meeting with Stalin; he urged them to confess, for old times' sake.
sentence2: Stalin urged them to confess, for old times' sake.