Janesville Police are investigating a pair of early morning robberies.  Police say a white male, wearing a black face mask up to his eyes, entered the Kwik Trip in the 2500 block of West Court Street just after midnight Wednesday, and threatened the clerk by pretending to have a weapon in his pocket.  Officers say the would-be robbery got nothing, but apparently then drove to the Kwik  Trip in the 200 block of East Memorial and did the same thing.  This time he was able to get away with cash and cigarettes.  Authorities say they have some pretty good surveillance photos of the suspect to share with the public.