Cat and the Canary, The (1927), directed by Paul Leni.
When you look into it you'll find a lot of the horror/thriller genre was established in the silent and early sound era. The work done then reverberates down the decades.
This is one of the original Old Dark House stories. The elements this time:
Spooky house, spooky housekeeper
Relatives gathered to read the will, 20 years later (can they do that?)
If the chief heir is shown to be insane the property reverts to a second unnamed heir, which gives everyone motive to drive the first heir crazy.
Fabulous diamonds are hidden somewhere.
People vanish without trace.
In the area, an escapee from the local asylum: the Cat, who rips people apart.
Not too heavy, not totally comic. A Harold Lloyd impersonator provides many of the laughs. Agile camera work from German Impressionism lifts it to a higher level.
I did not recognize anyone in the cast.
The set dressers went overboard on cobwebs: what's the housekeeper been doing all those years?
Adapted from a stage play, the movie was made again as The Cat and the Canary (1939). Another version -- The Cat Creeps (1930) -- is a lost film in both its English and Spanish language versions.
Available on Blu-ray from Kino with two commentary tracks. Good restoration.