The Ghost & Mrs. Muir (1968)

Season 1: Episode 4

Claymore brings a stranger to look at the house who claims he is a student of architecture and wants to take photos of the house. When he comes back to the house after the Muirs leave for the evening Captain Gregg thinks he's a burglar and tries to scare him away, not realizing that he is actually a parapsychologist who is determined to find the ghost of Gull Cottage and make him known to an unsuspecting public.