New dead ghost found while Paradox is the Daily Heroic mission, "Mystery: The Vault of Glass 3", in the Taken King expansion/TTK for Destiny.
This can be found after you defeat the boss and head to the traditional jumping puzzle in the Vault of Glass. You head up to the left in the cave, and circle around in it until you reach the ledge. From there you drop down to your right and there will be a little platform you can land on underneath you. Turn around and the ghost will be in the cave connected to the platform.
You must have obtained the first 2 without dying before you can get this one. This also leads to the No Time To Explain exotic pulse rifle / NTTE. Full guide for No Time To Explain here: https://www.youtube.com/watch?v=Va5KRSoV9Lw