For this achievement, you must play in a multiplayer lobby.
If done properly, you can get this achievement and the Mischievous achievement at the same time!
When you have someone die, you can ask a friend if you are in discord what the ghost was.
When you die in the game, you see the correct ghost that killed you!
Yes, that is a cheater method but, the only other way is to guess it properly and keep playing the match.