Always get expert forensic advice from a qualified person.
Make sure the plot has credibility; readers will notice litter tray stuff.
Huge signposting of clues is insulting to readers; subtle is good. But too many twists and layers and you have a ... Well let's not go there, eh?
Be careful with whom you engage when experimenting for investigation of the plot and put no one under any risk.
In all experimentation, do remember to use a control.