Skinner later confronts Mulder over the briefcase (which is now in Scully's possession), the absence of which has caused an international incident with Japan. He refuses to assist Mulder any further with his case. Mulder meets with Senator Richard Matheson, who gives him the details on the autopsy and links it with the larger conspiracy of the alien-human hybrids. Mulder investigates further, discovering that the Japanese scientists were members of the notorious Unit 731 during World War II; like Victor Klemper, they were recruited by the U.S. government to develop the hybrids. Mulder believes that the scientists killed on the videotape were working on a secret railway, transporting test subjects.