 After Yali's murders, Keth increased his efforts, while the "arurim" set up an undercover guard in Khapik, hoping to catch the Ghost in the act.With their combined efforts, a murder-in-progress was finally discovered and stopped, although the Ghost escaped.It was Tris who eventually caught him, and when Keth followed her, the Ghost was trapped to his thighs in the earth, and Tris was debating whether or not to kill him.