Star Wars: Shatterpoint

In the first of six novels set during the era of the Clone Wars, Master Mace Windu returns to his Separatist-occupied homeworld to investigate the disappearance of his former Padawan, Depa Billaba, who had been working as an undercover agent, and stumbles upon dark rumors of a massacre deep in the jungle that make him fear that Depa has succumbed to madness or to the dark side.