 The episode , which explores John Doggett 's backstory as a New York City police officer , was described as containing similar themes as those " explored on the Millennium series . " The episode guest @-@ starred Arthur Nascarella , who was a friend of series co @-@ star Robert Patrick . Patrick was essential in getting Nascarella cast on the show ; he later joked " I stole [ Nascarella 's ] New York accent in Copland [ sic ] and I stole it to do The X @-@ Files , but I got him cast in The X @-@ Files show . " 
