A new book about the University of Idaho murders claims that Bryan Kohberger had a single target the night he allegedly killed four college students. Journalist Howard Blum alleges in his upcoming book When the Night Comes Calling: A Requiem for the Idaho Student Murders that Kohberger had intended to only kill Madison Mogen because he passed the rooms of two surviving roommates, leaving them unharmed. “If he was just on a killing spree, it would have been natural, instinctive, to go to one of those doors,” Blum said. “Instead he goes up this narrow staircase and he turns directly into Maddie’s room, and I think Maddie was his target.” Blum also claims that Kohberger’s family, including his dad Michael, became concerned about his behavior leading up to his arrest. “[Michael] has been reading the headlines—he knows that four students were killed 12 miles from his son’s house. He knows what a troubled son he has,” Blum said. He claims that Kohberger’s two sisters spoke to their dad about suspicions but were ignored. Mogen, 21, was found dead in her bed alongside her best friend, Kaylee Goncalves, also 21. Housemate Xana Kernodle, 20, was also killed alongside her boyfriend Ethan Chapin, 20.