Okuru Kotoba
Ghost tries to get a message across to the living about someone dangerous whose still alive. The living characters end up trying to solve the mystery.

Diamond is Unbreakable
The same as the above but this is more Shounen -since there is fighting and actual action going on- then the above title.

Alternatively...
A ghost is going through a repeating day to solve a mystery or trying to remember something while stuck in a repeating day.

Recommend any dark stories! I've read Dusk Maiden of Amnesia btw.

Kouhii Muun no ghosts involved, but the entire story revolves around a time loop.

Thanks! 😁