...or they don't want to leave...
Suggest me stuff :)
The fantastic andibgoode also suggested some fitting tv show episodes:
Poirot: Peril at End House, The Mysterious Affair at Styles, Hercule Poirot's Christmas, Dumb Witness, The Murder of Roger Ackroyd, Sad Cypres, The Hollow, Taken at the Flood, Cat Among the Pigeons, Dead Man's Folly, The Labours of Hercules and Curtain.
Marple: 4:50 from Paddington, Sleeping Murder, The Sittaford Mystery, At Bertam's Hotel, Ordeal By Innocence, Towards Zero, A Pocket Full of Rye, They Do it With Mirrors, Why Didn't They Ask Evans?, The Pale Horse, The Secret of Chimneys, Greenshaw's Folly
Inspector Alleyn Mysteries: Artists in Crime, A Man Lay Dead, Final Curtain