When you write a mystery set in the past, you have to do it knowing what your detective would have known about solving crimes. It seems obvious but a detective going after Jack the Ripper wouldn’t have known anything about profiling or the psychology of serial killers. The problem is that you still have to write with these things in mind because they are a part of your reader’s knowledge.
What does this mean for my story set in the 1970s? I will have to find out:
- Whether or not blood evidence was used and tested for blood type.
- What were the prevailing theories about crime and criminals.
- What did they call PTSD? What were the theories about same?
- Suspects civil rights.
In spite of these things, I will have to write with the following in mind:
- My readers will have a set of expectations based on too much NCSI.
- No matter what the theories are about crimes and PTSD, my characters will have to behave in accordance to today’s theories/expectations.
My detective and her investigation have to mesh with the time period. She may be progressive or think in ways that are not typical for her time period, after all people are not part of a hive mind. But she cannot know things that have only recently been discovered.
The more I learn, the more that I realize — writing historic fiction is like walking a tightrope strung between then and now.