The lighthouse incident I was thinking of was the Ross Island lighthouse murder, in which reputedly the local (Kirkudbridghtshire) paper was supposed to have given the headline: "Lighthouse Keeper Found Slain: Other Keeper Missing, Police Baffled." Apparently the murderer haunts the lighthouse cottages; I met someone who was doing them up for holiday lets and apparently he used to materialise and look disapproving whenever he didn't like the choice of wallpaper.