Well, 'the hunt for a killer true story' might revolve around a specific case. It could detail the events leading up to the discovery of the killer, like the crime scenes, the victims' backgrounds, and the initial clues that set the hunt in motion. For example, it could be a story where a serial killer is on the loose and the authorities have to piece together various bits of evidence such as witness testimonies, forensic findings, and patterns in the killings to finally catch the culprit.
I'm not sure specifically which '1 5 killer' this refers to. There could be many cases in different regions. Maybe it was a serial killer case where the police had to hunt down the perpetrator through various means like forensic evidence, eyewitness accounts, and following up on leads.
There could be the victims or their families as well. Their stories and the impact of the crimes on them might be an important part of the narrative. Maybe the families were actively involved in pushing for the hunt to continue or provided crucial information. And of course, the killer is also a 'character' in a sense, even though their identity might be a mystery for a large part of the story.