 Mulder deduces that the birthdays of all the victims match up with the dates of the Witches ' Sabbath , meaning that continued murders will occur . Back at the clinic , another patient is murdered when her face is melted by acid . With no suspects left to turn to , Mulder uses the hospital 's computer program to determine what Franklin would look like under heavy plastic surgery . He is shocked to find that Franklin is actually Dr. Cllifford Cox , a cosmetic doctor who presumably died during the first spree of murders . Cox attempts to murder his fifth and final victim in a quest to gain eternal youth . He removes the skin on his own face , using a ritual to make him appear younger . Cox is never caught , with the episode ending with him successfully applying at another medical hospital . 
