In The Dark Tower, the evil forces of Matthew McConaughey try to capture the main protagonist across different planets. At one point, they find his apartment and murder his relatives who are living there, then ransack the apartment. However, for some reason they leave, instead of laying an ambush knowing that he will eventually return there.
What is the reason for not lying in wait for Jake at his apartment?
I guess that the 'evil forces' did not expect the boy to come back to his home so soon since he was trying to escape them. Additionally, his emotional reaction to the death of his mother acted as an alarm that alerted Walter about his presence there - so they did not ambush him but they did set a trap. That is only my interpretation however and, not having read the books, I don't know if this is also what happens in the original story. Maybe the books have a better explanation.
