Fans of the TV show "Blue Bloods" are expressing their interest in a prequel series focused on a young Frank Reagan, the commissioner played by Tom Selleck. The show, which has been on for over a decade, follows the Reagan family and their involvement in law enforcement. Many fans believe that a prequel series could explore the early days of Frank on the force and his relationship with his late wife. While some are skeptical about the idea, the consensus among fans is that a prequel series would be a great addition to the "Blue Bloods" legacy.