I am trying to identify a film I saw multiple times on television in the 1960s. It was black and white, with an urban setting, and concerned a man who (maybe, maybe not) was residing with a family that had two children, a boy and a girl. I believe that their mother may have been murdered as the children's rhyme "Step on a crack, break you mother's back," was featured ominously. There was also some sort of signalling going on where a doll was placed in a window at night. Any ideas? I thought the name included "street," but have been unable to find it.