 The episode was written by Sara B. Charno , making it her first writing contribution to the series . The episode was directed by Rob Bowman . Charno initially developed a story revolving around the concept of 50 year old murders and the transfer of genetic memory . This was later combined with a separate concept about a female serial killer . Glen Morgan and James Wong , who had written for The X @-@ Files before , provided additional contributions to the story . The script was revised shortly before shooting , resulting in newer scenes being added , such as the scene where BJ attacks Mulder . 
