The Spy Purge

The Spy Purge was a recent and very notable event in the history of the Keizon Empire. Some decades after the nation of Korinder surrendered to Empire rule, the Senate discovered that hundreds of their citizens, trained in espionage, had intentionally infiltrated the inner workings of the Empire with the purpose of bringing it down from within. The discovery came at a time just when the Korinder spy network was poised to strike.
The Empire, however, was able to make its move first, and the Spy Purge was the result. Any adult citizen of Korinder who had potential access to even a small amount of valuable intelligence was rounded up and executed for treason. Little to no evidence beyond that circumstance was considered to be required, the Senate's orders issued on a principle of better to be too thorough than risk not being thorough enough. Given the sheer audacity at the attempt to topple the Empire from within, burning the traitors alive was chosen as the method of execution (hanging being the more typical method).
The people of Korinder were "demoted" in the Empire's ethnic hierarchy and any remaining in Keizorna over the age of 13 were deported back to their home territory. The outcry in Korinder over the mass executions led to it becoming a conflict territory. The Senate is constantly seeking to track down those few spies (or suspected spies) who managed to escape the Purge; not just for the sake of justice, but because they fear what intelligence those escapees could hold and the damage that could be done to the Empire should that knowledge be passed on to someone who could act on it.
The children remaining were placed in the custody of Echelfa nobility, to be "cleansed" of their parents' indoctrination and raised in Empire loyalty.