The king threw them in/into the 'dungeon'.
(..) If you would, I would like you please, to lead Miss Parkinson and the rest of Slytherin house, from the hall. Exactly where is it I'll be leading 'em to, ma'am? The dungeons would do. I presume you have a reason for returning, Potter. What is it you need? Time, Professor. As much as you can get me. (..)2011 Harry Potter and the Deathly Hallows: Part 2