Paranormal Witches Grave in Skiatook OKlahoma Haunted
From the channel of URBEX and Broken Things.
I'm not sure if being "cased in concrete" is necessarily a means to ensure that a grave isn't disturbed. I've seen several such slab graves. A few were located in a cemetery not too far away from a long-abandoned seminary. At any rate, the video at the top of the included video is very interesting.