A woman in the City is killed. Throat slit, stabbed repeatedly. Number 'seven' written above her head, like the other victims.
And then Gibbs is attacked. He's eight. The note says that on the envelope, and has a letter inside it.
Ume comes across Willie. But instead of stabbing him, she snaps his neck. It's quick, and painless. She closes his eyes with her fingers, and then heads back to Tom's apartment.