Patriach: Offered curses, threats. No useful information. Died during interrogation.
Older Daughter: Broke quickly. Showed promise. Sadly, knew nothing. Died after interrogation.
Older Son: Killed self before interrogation could commence. Sloppy. Must remember to acquire new manacles.
Youngest Son: Revealed hidden entrance beneath great hall. Possible link to Library. Will keep alive until story is verified.
Morning Addendum: Verified son's story.