Black & White movie set in America black & white girls become friends on a beach

Trying to find the name of a movie I believe was made in the 1930's or 1940's in which a man murders an old woman and cements her into a fireplace.I remember seeing this movie only once about twenty years ago.

I saw this old movie about a year ago, it was black and white and about this women who was married to an over protective preacher who made her pray then killed her one day after her first husband (i think) stole a lot of money. The children ended up running away from the preacher who ended up being...

The only thing I remember are there were 3 or 4 people scuba diving. When they came up there was no one left on earth. The plant life was dead or dying. No air. They left on their tanks then the plants started to come back and their was air. They were alone and had to find a way to stay alive....

I need to find out the name of an old black and white movie of a little girl who is evil. She ends up killing a grounds keeper and a classmate because she wanted his award?

I watched an old B & W movie about man who played a "downtrodden" individual to find out what it was like to live such a life. It was a social experiment on his part but he was really a movie director. A lady (his co-star) bought into his plight in life, initially. She bought him some coffee...