These 6 murders took place in the same geographical area as a series of serial killings 15-16 years later. Both killing sprees were only of African-American women or girls.
Rather interestingly in the Freeway Phantom note, the killer taunts the authorities that he will admit his other murders if he ever got caught. It must be absolutely galling to him that say his Zodiac Killer crimes are attributed to a Richard Gaikowski. Just imagine, Gaikowski is going to be world famous forever as the Zodiac Killer and the real killer is going to be a complete nonentity !