Zelenskyy said that his decisions were based on the sheer volume of treason cases and cooperation with Russia that had been uncovered. He said that “651 criminal proceedings have been registered in Ukraine on charges of treason and collaboration activities of employees of the prosecutor’s office, pre-trial investigation, and other law enforcement agencies. In the framework of 198 criminal proceedings, suspicions were [raised with] the relevant persons.” Zelenskyy added that over 60 employees of the prosecutor’s office and the SBU had remained in territories occupied by Russia and were working “against our state.”
Source: Behind Zelenskyy’s Security Shakeup – by Olga Lautman