=--=--=--=--=--=--=--=--Baron von Harkonnen Murdered!--=--=--=--=--=--=--=--=-
      ID:        harko_clue
      Old name:  Baron von Harkonnen murdered!
      Points:    3
      Planet:    Giedi Prime
      Solved(2): Kain,Radiant
      Old hint:
  Baron von Harkonenn IX has been murdered! The murder took place last
  evening at the Harkonnen Estate on Giedi prime. Apparently Baron von
  Harkonenn IX was not well liked and there are several suspects being
  detained at the  Estate. Travel  there and  aid Inspector Snyder in
  his investigation.
=--=--=--=--=--=--=--=--Baron von Harkonnen Murdered!--=--=--=--=--=--=--=--=-

It is fairly straightforward if you're familiar with the boardgame “Clue”.

The manor is 2w alls from GP AP.

Inspector Snyder is, unhelpfully, hiding in one of the several secret passages. <spoiler> It is s, all w, 'open curtains' from the manor entrance. </spoiler> After you find him you must, like in “Clue” obtain cards. You can either find them by searching or just kill everything in sight. There are 20 cards.

After you have the cards, compare the ones you have to three lists found in the manor. <spoiler> First is on the kitchen table. Second is in the lounge. Third is in the Study. </spoiler> Return to Snyder and say “Guess” once you've figured it all out.