What was the "evidence" against Sarah Good?

When pressed to name names, Sarah Good becomes an easy
target for the girls.  Like Tituba, she is of a lower social status than the rest of the
town.  As a ragged, homeless woman, she is often ignored or dismissed as being crazy. 
Since people in the town already questions Sarah Good's Christian character, the
assertion that she works for the devil is easily accepted and not put into question. 
Once the lower rungs of society are out of the way, the girls turn their claims towards
more respected women like Elizabeth Proctor.