He knew Conan's secret ever since the elevator time bomb incident. Conan must be an alien! He would admit that Conan's acting was rather good, but since aliens were higher life forms his intelligence was rather remarkable. He figured he must be scouting the planet for an invasion. Investigating crimes was this alien's pastime. He seemed to enjoy pretend to be Kogoro. He figured as long as he complied with Conan the alien's request he might be spared when his alien family invaded the planet Earth. Though he might not be around to do so. After all, Conan did say he'd only tell him in the afterlife.