There have been two more murders.
Two prostitutes: Polly and Annie. Emma, who witnessed Bea being murdered, left Calais and is now in Whitechapel. She is not a prostitute any more, but now she makes a living by picking gentlemen’s pockets. Emma knew both Polly and Annie. Emma and Polly used to share lodgings in Whitechapel, and Annie was a friend. Actually, the night that Annie is murdered, she gets to see the man who her friend went with, and then she remembers it is the same man she witnessed killing Bea. So she runs, trying to warn Annie, but she is too late, and Annie is already dead.
Emma has also come across with the other two main characters in the novel. She met Cora when Cora snuck into the mortuary. Actually, she was the one who told her Martha’s name, and then again she meets her when she goes to check where Polly was murdered. This time they talk, and Cora tells her about her father being a policeman and gives her some food. Emma then asks her about Martha’s things, and it is now that we learn that Martha, who also knew Emma, stole the envelope that Cora found among her things and then left for Alice. Cora denies knowing anything about the envelope and the pendant, and even though Emma knows that she is lying, she doesn’t press her.
Emma also gets to meet Alice. After Annie’s murder, Emma is frightened and she goes to the shelter, trying to find some help. She is a terrible state, and when Miss Lawler, the woman running the shelter, introduces Emma to Alice, Emma recognizes the name as the one on the envelope she took from Bea, and she also sees the resemblance between Emma and Bea, so she panics and flees from the place. Alice, though, thinks that Emma has reacted that way because she must have recognized her name as she knows something about Bea, so I imagine that Alice will want to talk to Emma and find out the truth about her sister.
So in this book Jack the Ripper apparently comes from Calais, or at least, it is implied that he killed in France before.