Cold Case of a Serial Killer's Daughter Solved in New True Crime Book

Sheryl 'Mac' McCollum, American criminal investigator and host of the podcast Zone 7, will publish Swans Don't Swim in a Sewer: Solving the Cold Case of the Flint River Killer's Daughter on May 12, 2026. The book is a documentary account of one of Georgia's most complex and disturbing cold cases — involving a serial killer's daughter whose fate went unresolved for years, and a skull that authorities had long misidentified.

A lifelong mission for one investigator

McCollum — known to most simply as 'Mac' — is not a typical true crime author. She is a trained criminal investigator who has spent decades working unsolved cases, both professionally and as a volunteer. Her podcast Zone 7 has built a dedicated following drawn to her methodical, evidence-based approach to cold cases: cases that have been shelved, forgotten, or mishandled by the system.

In her podcast episodes covering the Flint River Killer case, McCollum describes how critical errors in the initial investigation — including the misidentification of the skull — kept the victim's true identity hidden for years. It was precisely this kind of systemic failure that drove McCollum to dig deeper and ultimately crack the case.

For readers interested in true crime books, McCollum's work stands as a compelling example of how systematic, evidence-based investigation can bring resolution to cases officially considered unsolvable.