What does Vera find in her room and why might it be important ?

Vera finds a nursery rhyme framed and hanging above the clock. The rhyme is the Ten Little Indians. This is important because it foreshadows what will come.

A mantelpiece bare of ornaments save for an enormous block of white marble shaped like a bear, a piece of modern sculpture in which was inset a clock. Over it, in a gleaming chromium frame, was a big square of parchment - a poem.