The showrunner revealed to TV Guide that Quinn (Desmond Harrington) has a past relationship with a new character, club manager George (Jason Gedrick).
"When the Miami Metro has to investigate the killing of a fellow police officer, it leads them to one of Isaac (Ray Stevenson)'s clubs that George manages," Colleton explained.
"Quinn knows George from his days in narcotics because, along with it being a driving nightclub stripper business, it's also a place where the Ukrainian mob laundered a lot of money and passed its drugs and guns and all sort of things."
Colleton added that "everyone's plot is thickening" in the serial killer drama's new episodes.
It was recently announced that Dexter will conclude after eight seasons, with Colleton describing season seven as the first half of "a two-season series-ender".
Dexter returns to Showtime on Sunday, September 30 at 9/8c. In the UK, the series airs on FX.
