Identify this movie? Old dark house genre.

I saw this some time ago and it has made a home in my head. I want to watch it again to exorcise it. This cheap and cheesy movie is from the 40’s probably, and I don’t think there is anyone of note in the cast, except possibly the black houseboy, his comic turn looked familiar.

Oh, there will be massive spoilers.

So the premise is the insane brother of a matriarch has escaped the loony bin and the authorities are expecting him at the old dark house where the matriarch lives. There are two or three grasping greedy relatives and their spouses visiting, or about to arrive, The brother manages to sneak in and is welcomed by the matriarch, who disguises him as the new butler (the others haven’t seen him for a very long time if at all). People start dying right and left. Some of them are in search of treasure that is supposed to be somewhere there, and some are scheming to inherit the estate (or something like that). Turns out the matriarch is just as nuts as her brother, and between them they kill off everyone except the houseboy, an innocent young woman (niece? companion?) and her outsider beau, before the end.

The key thing that has stuck in my head is a feature of the house: it is apparently built so that it extends over a rocky seashore that is maybe a few hundred feet below (really, it wouldn’t be practical to have such an arrangement, but it was necessary I guess, for the plot.) There was at least one trap door in the floor, and it was triggered by some device or other, and three people (I think) went down it. The first one we just see disappear screaming. The second and third we see them falling from above the hole, and whatever special effect they used was pretty chilling to me at the time.

I’ve checked IMDb’s list of old dark house movies and I don’t think it’s there.

Does this ring a bell with anyone?

The Hidden Hand (1942)

Thank you, and I had forgotten a young Craig Stevens was in it. I’m curious how you found it. Are there specific search terms I could have used?

Assuming you’re using the ‘keyword’ search at IMDB, you provided several in your OP. I’m pretty sure I used ‘Trapdoor’ and then when the suggested keyword pairings came up, selected ‘murder.’ Then is was just a matter of finding results from the 1940s. I’ve never seen the film, but when I saw Willie Best in the credits, that nailed it down.

Great username and subject in OP.

Ah, I didn’t even think of that when I posted. I’ve mentioned that connection in the various threads of “what does your user name mean?” but it never seems to resonate with anyone.

Hey, it’s one of MY favorite movies.

Have a potato.