It happened on a frigid winter night. First, a sudden moment of terror. Then, a frantic search to find a costumed killer. “Internal Affairs,” Dateline’s next original podcast series, takes us to northern Colorado, and into an obsessive and deadly romantic affair. Reported by Josh Mankiewicz, it’s a story about bad choices, a fatal attraction and men and women who proudly wore badges at work--while living lies at home. And when the day of reckoning came, the people with the badges had to investigate their own.