I'm not sure specifically which 'nanny killer true story' you are referring to. There could be many cases around the world involving something like this. It might be about a person who killed a nanny for various reasons such as financial gain, personal grudges, or mental instability.
Since I don't know which 'nanny killer true story' you mean, I can't give a lot of details. But generally, in such stories, investigators would look at things like the nanny's background, the people she interacted with, and any signs of struggle or motive at the crime scene. There might be witnesses who could provide information about the events leading up to the killing.
Yes, it is. There are many real - life cases where nannies have engaged in devious behavior. Some nannies might steal from the families they work for, or mistreat the children in their care. In the 'Devious Nanny' story, it could be based on actual events where a nanny had ulterior motives, like trying to get access to family secrets or financial gain at the expense of the family's well - being.