The released slaves are the ones that are captured by the dirty nobles. Unfortunately, these nobles are very good at covering their tracks. Most of the slaves didn't know who their captors were.
Even if they knew, they were forced to sign the expensive soul contract to prevent information leaks. This may look like a wasteful and troublesome movement. However, Angus could see this as just another ploy by other nobles.
Most of these slaves were found inside the inhabited area. Still, some were released near Freyspire City, his hometown and Victory's dukedom. Even Angus, who is not following the current politics, could smell a dirty conspiracy from miles away.
However, Angus also didn't surprise at this. Over the last few years, Victory's noble family influence spread to many fields because of seventh-grade Jade, the Sur Knight squad, and Angus's fame.