Alexander Ross
From superman.nu: Supermanica
One of the occupants of Clark Kent's apartment building at 344 Clinton Street in Metropolis, a dilettantish and overzealous correspondence-school sleuth who becomes suspicious of Clark Kent's secretive comings and goings and decides he must really be a master criminal posing as a journalist.
Fearful that Ross's snooping may inadvertently expose the secret of his dual identity, Superman quiets Ross's suspicions by assuring him that Kent's unconventional schedule reflects merely his partnership with Superman in rooting out crime in Metropolis (S No. 112/1, Mar 1957: "Superman's Neighbors").