My wife and I seem to be able to remember a movie that was on HBO in the late 70's or early 80's... the details we remember
An apartment building
Seniors
We think the seniors may kill as well?

One scene we remember is them burying a person in cement, but forgetting the fingertips are sticking out, so they chop them off!!

Brilliant!

Please help...
Jason and Johna Bittner

Homebodies (1974) (http://www.imdb.com/title/tt0071617/)

YES, that's it! Great, thanks so much!!

You're very welcome.