Bolla Ropal was the keeper of the Kyber Crystal, which stored the identities of Force-sensitive children known to the Jedi. After stealing a Holocron from the Jedi Temple on Coruscant, the bounty hunter Cad Bane captured Ropal.
To access the information about Jedi children, Bane needed Ropal to open the Holocron, into which he'd insert the crystal. Ropal refused despite being tortured by Bane's battle droids, sacrificing his own life to thwart the bounty hunter's plans.
Bounty hunter Cad Bane was hired by the Sith to track down a Jedi holocron as well as the data crystal in Bolla's possession. Bane tortured Ropal to death when the Jedi refused to open the holocron.
As a Jedi Master, Bolla was literally entrusted with the future of the Jedi -- a roster of children across the galaxy with great Force-potential.
Darth Sidious planned to use the information contained in the Kyber Crystal to enslave Force-sensitive children in the hopes of creating a league of spies loyal to the Sith.