Badge of Blood follows Detective Alicia Mbeki, a rookie detective investigating a disturbing series of five murders committed within two months. The victims have been strangled with belts, but Alicia's senior partner, Detective Dan Vermaak, repeatedly attempts to dismiss the deaths as suicides. Their conflicting approaches create tension within the police department, while Alicia's determination to solve the cases places her career at risk. After Captain Roth warns Alicia that her promotion depends on solving cases, she begins examining the evidence more closely. She notices a connection between the victims: each woman was strangled with a belt, leaving distinctive markings around the neck. Alicia then discovers a dismissed domestic-assault case involving Dan's wife, Lauryn, who was also strangled. This discovery makes her suspicious of Dan and his attempts to prevent further investigation. Despite being ordered to stop investigating, Alicia secretly returns to a crime scene and discovers a belt buckle that may provide crucial evidence. When Detective Sibusiso Dlamini attempts to retrieve it, Alicia confronts and arrests him. The evidence is sent for forensic testing, eventually revealing Dan's connection to the murders. Before Alicia and Captain Roth can intervene, Dan confronts Sibusiso during interrogation and reveals himself as the killer. Dan explains that his wife was murdered, but her case was dismissed as suicide. Believing that the police failed her, he killed other women using the same method as an act of revenge. When Dan attempts to kill Sibusiso, Alicia shoots him to save his life. Following Dan's arrest, Alicia is promoted for solving the case. However, while examining Lauryn's case file, she discovers new information that causes her to question whether Dan was truly the original killer. The film ends on this unresolved revelation, leaving open the possibility that the real serial killer may still be at large and that the corruption surrounding Lauryn's murder runs deeper than Alicia initially believed.