What was Molly's Crime?

Wemmick tells the story of Jaggers' woman servant, the "tigress" as Wemmick refers to her. It was Jaggers' first big break-through case, the case that made him. He was defending this woman in a case where she was accused of killing another woman by strangulation. This is why Jaggers' likes to show off the poor woman's hands to company. The woman was also said to have killed her own child, a girl, at about the same time as the murder.